Research ArticleStudy on Double-Shear Test of Anchor Cable and C-Shaped Tube
Renliang Shan Yongsheng Bao Pengcheng Huang Weijun Liu and Gengzhao Li
School of Mechanics and Civil Engineering China University of Mining and Technology (Beijing) Beijing 100083 China
Correspondence should be addressed to Pengcheng Huang huangpengchengstudentcumtbeducn
Received 10 March 2021 Revised 21 April 2021 Accepted 15 May 2021 Published 27 May 2021
Academic Editor Zhixiong Li
Copyright copy 2021 Renliang Shan et al(is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
(e free section of prestressed anchor cable is a weak part of support A new supporting structure named Anchor Cable andC-Shaped Tube which can bear transverse shear force solves the problem that rock bolt and anchor cable are prone to shearfailure in the free section and also solves the contradiction between high preload and low shear bearing capacity of supportmaterials Double-shear tests of Anchor Cable and C-Shaped Tube with smooth joint planes were carried out Double-shear testswere carried out on the anchor cables with the diameter of 216mm and the same type of Anchor Cable and C-Shaped Tube underdifferent preload conditions (e influence of the preload on the shear performance of supporting materials and the enhancementeffect of Anchor Cable and C-Shaped Tube supporting structure on the shear performance of anchor cables were analyzed(e testresults confirm that Anchor Cable and C-Shaped Tube can improve the transverse shear resistance of the supporting material andincrease the axial ultimate bearing capacity of the anchor cable during the shearing process It is found that during the double-shear test the fracture form of the supporting materials is tensile fracture and when it is sheared Anchor Cable and C-ShapedTube can reduce the stress concentration of the interaction between the joint surface and the surrounding rock and reduce thedamage to the surrounding rock
1 Introduction
(e use of rock bolts and anchor cables has become an im-portant and main support method for coal mine roadwaysupport [1] With the increasing depth of coal mining thechangeable geological structure in the environment of deepunderground the complex stress environment and the largecommon deformation and failure of surrounding rock appearwhile the conventional supporting methods show limitations[2 3] Due to the inadaptability of ordinary anchor cables of thelarge deformation environment of surrounding rock thebreaking phenomenon occurs constantly and the forms aredifferent [4] Besides the most common tensile breaking thereare also a large proportion of shear breaking tension bendingand tension-shear combined breaking forms [5ndash9]
At present in the design of roadway support most of themonly put axial bearing capacity into consideration withoutshear bearing capacity of rock bolt and anchor cable and theshear fracture of rock bolts and anchor cables cannot be ig-nored [10] Some studies have found that the fracture location
of the anchor cable or rock bolt occurs at the position of the freesection near 2 meters above the roof of the roadway [11] andother studies have found that the ultimate bearing capacity anddisplacement of anchor cable will decrease with the increase ofprestress [12 13] which improves the probability of shearbreaking of anchor cable (erefore the free section of theprestressed anchor cable is a weak link that is susceptible toshear failure Lin et al studied the anchorage stress and de-formation of the anchorage joint under shear action throughdirect shear test and found that the inclination angle of the bolthas an effect on the shear strength of the joint plane andimproved the shear creep model of rock-like materials [14 15]
In order to adapt to the large deformation characteristicsof deep surrounding rock many supporting materials andsupporting technologies have been invented by experts andscholars For instance anchor bolt with constant resistanceand large deformation and NPR boltscables invented by Heet al well solved the problem of large deformation in deepsoft rock roadway [16ndash18] Also the team of Kang et alfound that the prestress of rock bolt and its diffusion played a
HindawiShock and VibrationVolume 2021 Article ID 9948424 10 pageshttpsdoiorg10115520219948424
decisive role in supporting effect and proposed a highprestress and high strength supporting system whichachieved good results in many work sites [19ndash21] Most ofthese technologies and materials aim at controlling the largeaxial deformation of surrounding rock but seldom considerthe transverse loading of supporting materials In order tosolve the contradiction that the supporting material in freesection is easy to break and the transverse bearing capacityand transverse displacement of the supporting material areeasy to decrease due to high prestress [11ndash13] a supportingstructure named Anchor Cable and C-Shaped Tube wasinvented to solve the problem that the anchor cable withhigh prestress in free section is easy to shear and break (eshear mechanical properties of the supporting structurenamed Anchor Cable and C-Shaped Tube were studied bydouble-shear tests in laboratory In this provision AnchorCable and C-Shaped Tube shall hereafter be referred to asACC
2 Brief Introduction of ACC and Analysis ofIts Mechanism
21 Brief Introduction of ACC Supporting Structure ACCconsists of two parts anchor cable with high prestress andC-shaped tube Figure 1 shows the physical drawing andschematic of ACC (e anchor cable with high prestressexerts axial compression force on the structural plane ofsurrounding rock by prestress which increases the frictionbetween joint planes prevents the surrounding rock fromdislocation on both sides of the structural plane togetherwith the dowelling function of anchor cable itself andprevents the surrounding rock from axial shearing dislo-cation (e C-shaped tube is installed at the free end of thestructure which separates the exposed part of anchor cableor rock bolt from surrounding rock [22] When sheardislocation occurs in surrounding rock it would be sepa-rated from the free end of anchor cable or rock boltWith theshear deformation of the structural plane the C-shaped tubeshrinks gradually to completely wrap the anchor cable thusimproving the shear stiffness and increasing the shear ca-pacity of the free end of the supporting structure
22 Analysis of the Mechanism of ACC After ACC is sub-jected to shear force the shear part of slotted steel tubeshrinks continuously and wraps the internal anchor cable(Figure 1(b)) When the free section of anchor cable bearsshear force it is restrained by locks and anchoring section atboth ends At this time it could be seen as the simplysupported beam under concentrated force Assuming thatthe concentrated force acts in the middle of the simplysupported beam and the length of the free section of anchorcable is l (m) according to the relevant formulas of materialmechanics the stress situation of anchor cable at the shearplane in elastic stage can be deduced as follows [23]
M FSl
4 (1)
σ 32M
πD2 + σ1
8FSl
πD2 + σ1 (2)
τ FS πR
221113872 1113873(4R3π)
Iz2R
FS πR221113872 1113873(4R3π)
πR441113872 11138732R
4FS
3A
(3)
It can be seen from formula (2) that when the shear forceis fixed the tensile stress on the anchor cable decreases withthe increase of its diameter After installing the slotted steeltube when it shrinks and deforms the shear force acts 0 kNon the anchor cable due to its certain bearing capacity Itindicates that ACC can absorb a certain shear load to protectthe anchor cable and its limit is Fs1 (kN) It can be seen fromformula (4) that the contracting stiffness of slotted steel tubeK (kNm) could be obtained by experiment When theslotted steel tube and anchor cable form the bearingstructure the diameter of the supporting material is in-creased and the additional axial force is reduced [23]
FS1 KZ 2K R2 minus R2prime( 1113857 (4)
It can be seen from formula (3) that the shear stress ofanchor cable decreases with the increase of cross-sectionalarea which of the whole supporting structure increases dueto the installation of slotted steel tube so ACC bears lessshear stress on the shear plane under the same shear force
M is the bending moment (Nmiddotm) of the anchor cable onthe shear plane FS is the shear load (N) on the anchor cableσ1 is the initial axial stress (Nm2) caused by prestress ofanchor cable and D (m) is the diameter of anchor cable τisthe shear stress (Nm2) of the anchor cable on the shearplaneIz is the moment of inertia relative to the neutral axis(m4) R1 (m) is the inner diameter of slotted steel pipe beforeshrinkage R2 (m) is the outer diameter the inner diameterafter shrinkage is R1prime (m) and the outer diameter is R2prime (m)
3 Brief Introduction of Double-Shear Instrument
(e schematic diagram and physical drawing of the self-designed and developed double-shear test system-tensionand shear system of Anchor Cable (bolt) and C-shaped Tubeare shown in Figure 2 In this system the anchor cable istensioned by locks in the same way as in the work site toprovide prestress to the supporting materials (emaximumaxial tensile load is 120 tons and it equips a vertical loadingsystem with a maximum vertical load of 600 tons in themiddle (is system can apply shear force to the supportingmaterials and the maximum shear displacement is 250mm
(e test samples are 3 concrete specimens of the samesize 300mmtimes 300mmtimes 300mm with 32mm prefabricated
2 Shock and Vibration
holes in the middle in which the supporting materials areinstalled for further tests (e test samples are restrained bythree independent stainless steel shear boxes (Figure 2) andthe shear boxes on both sides are restrained respectively by
four beams and four screws It can be seen from theschematic diagram in Figure 2(a) that the instrument has noforce on the prefabricated joint plane but pure shear force sothe smooth joint plane is what the experiment studies
Vertical loading system
Normal force
The lock of theanchor cable
Concrete test block
Beams for fixing
Axial force
Supporting materials
The base
Screws for fixing
Precast joint surface Shear boxLoading end of
horizontal tensionsystem
Fixed end ofhorizontal stretching
system
(a)
Beam forfixing
Screw for fixing Precast joint surfaces
Loading end ofhorizontal tension
system
Fixed end ofhorizontalstretching
system Shear box
(b)
Figure 2 Sketch map of tension and shear system of Anchor Cable (bolt) and C-shaped Tube (a) Diagram of instrument (b) Physicaldrawing of the instrument
C-shaped tube Anchor cableSupport plate
Anchor
(a)
Before the load After the load
Fs Fs
Z
R2 R
2 prime
R 1 R 1prime
(b)
Figure 1 Physical drawing and schematic of ACC (a) Physical drawing of the ACC (b) Schematic diagram of action form of ACC
Shock and Vibration 3
4 Test Design and Preparation
In this experiment double-shear tests were carried out onanchor cables with the diameter of 216mm and the sametype of ACCs in order to study the influence of differentprestress on the shear performance of anchor cable andanalyze the effect of ACC supporting structure on the shearmechanical properties of anchor cables after the addition ofC-shaped tube into ACC supporting structure Table 1 is thetest design table for this experiment (e specification ofconcrete specimen used in the test was300mmtimes 300mmtimes 300mm and the ratio of water cementsand gravel was 1 2 4 4 After pouring the specimen a100mmtimes 100mm small specimen was left for uniaxialcompression test to determine the uniaxial compressivestrength of the large specimen which is shown in Table 1(e uniaxial compressive strength of the test block wasdetermined as 30MPa according to the results of uniaxialcompression test and some test blocks are shown inFigure 3
5 Analysis of Test Results
(e test results are plotted in Figure 4 and summarized inTable 2 after the experiment Due to a certain gap betweenthe test block and the shear box there will be a stage wherethe shear displacement increases while the shear force re-mains unchanged during the test and the effective sheardisplacement in the table refers to the shear displacementwithout this initial stage of the test
51 Breaking Law of SupportingMaterials (e breaking lawof the anchor cables with the diameter of 216mm in double-shear test is as follows It can be seen from Figures 4(a) and4(b) that it is not the same for the law between the curves ofshear force-shear displacement and axial force-shear dis-placement (e shear force-shear displacement curve isdivided into three stages elastic stage (Figure 4(a) A) shortshear yield stage (Figure 4(a) B) and fracture stage(Figure 4(a) C) (e axial force has a relaxation stage(Figure 4(b)A) with the increase of shear displacement(isrelaxation phenomenon is more common with the increaseof prestress of anchor cable (e reason for the relaxationstage is that a part of the prestress will be transformed intoresistance to the deformation of joint surface in the initialstage of shear deformation and then it will enter the elasticstage (Figure 4(b) B) followed by the long plasticstrengthening stage (Figure 4(b) C) and finally break(Figure 4(b) D)
(e breaking law of ACC of the anchor cables with thediameter of 216mm in double-shear test is as follows
As can be seen from Figures 4(c) and 4(d) the rela-tionship between the shear force-shear displacement curvesof ACC has gone through four stages Stage A is stiffnessstrengthening stage (Figure 4(c) A) Stage B is elastic stage(Figure 4(c) B) Stage C is shear yield stage (Figure 4(c) C)Stage D is fracture stage (Figure 4(c) D) and the four stagesare same for the axial force and anchor cable shown in
Figure 4(d) In the stage a of shear force-shear displacementcurve when ACC is under shear load the slotted steel pipecan shrink with the increase of shear displacement to wrapthe anchor cable so that the slotted steel pipe and the anchorcable can bear the load together which improves the initialshear stiffness of the support material
52Analysis ofMaterialFailureMode Breaking the concreteafter experiment it is required to analyze the failure mode ofsupporting material and concrete blocks Figure 5 showssome representative blocks and supporting materials afterdemolition Figures 5(a) and 5(b) correspond to the testnumber DS3 and Figures 5(c) and 5(d) to the test numberDS8 which are the double-shear test breaking diagrams ofanchor cables with the diameter of 216mm and the sametype of ACC under the prestress of 200 kN
(e failure mode of concrete block is as followsIt can be seen from Figures 5(a) and 5(c) that in the
process of double-shear test severe plastic compressionfailure occurs at the lower part of the shear plane near thejoint surface of the left and right concrete blocks and theupper part of the shear plane on the left and right sides of theintermediate block which result from directly being affectedby supportingmaterial and it becomes a cone-shaped failureplane
During the double-shear test the intermediate block iscontinuously subjected to the reaction force of supportingmaterial Plastic deformation occurs continuously on con-crete blocks until the whole block splits from parallel drillingdirection because the stiffness of it is lower than that of thesupporting material However due to the limitation of theshear box the test block can still apply the load on thesupporting material the test block continues to expand andthe crack continues to expand until the supporting materialis broken
Crack propagation mode of the test block indicates thatthe cracks of the concrete block are radial after the double-shear test of the anchor cables with the diameter of 216mmwhile those of the concrete block of the ACC of anchorcables with the diameter of 216mm are split (is is becausethe anchor cable is structured by many steel strands whichmakes uneven reaction force on the surrounding rock andincreases the possibility of stress concentration Howeverthe C-shaped tube of ACC is circular which can reduce thedegree of stress concentration and the damage to sur-rounding rock
(e failure mode of supporting materials is as followsIt can be seen from Figures 5(b) and 5(d) that the
supporting material presents with the shape of spreadingwing after being sheared and is broken near the shear plane(rough the analysis of the fracture of two kinds of sup-porting materials it is found that there is obvious neckingphenomenon in the fracture of two kinds of anchor cablesand the anchor cables are tensile fracture ACC is protectedby slotted steel pipe When subjected to shear force theC-shaped tube near the shear plane shrinks to wrap theanchor cable and bear the load together with the anchorcable When anchor cables break successively inside there
4 Shock and Vibration
Table 1 Double-shear test schedule
Number Material type Prestress (kN) Average uniaxial compressive strength of specimen (MPa)DS1 Anchor cables with the diameter of 216mm 100 31DS2 ACC with the diameter of 216mm 100 28DS3 Anchor cables with the diameter of 216mm 150 32DS4 ACC with the diameter of 216mm 150 30DS5 Anchor cables with the diameter of 216mm 200 33DS6 ACC with the diameter of 216mm 200 33DS7 Anchor cables with the diameter of 216mm 250 32DS8 ACC with the diameter of 216mm 250 32DS9 Anchor cables with the diameter of 216mm 300 31DS10 ACC with the diameter of 216mm 300 31
Small concretestandard test block
A reserved holewith a diameter of
32mm
Large concretestandard test block
Figure 3 Part of the test blocks
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
A
B
Load
(kN
)
Vertical displacement (mm)
Vertical load of DS1 100kNVertical load of DS2 150kNVertical load of DS3 200kNVertical load of DS4 250kNVertical load of DS5 300kN
C
(a)
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
DA B
Load
(kN
)
Vertical displacement (mm)
Axial load of DS1 100kNAxial load of DS2 150kNAxial load of DS3 200kNAxial load of DS4 250kNAxial load of DS5 300kN
C
(b)
Figure 4 Continued
Shock and Vibration 5
are no steel strands supporting on one side of the internalC-shaped tube But at this time it has been locked by theexpanded rock sample to bear both shear and tension forceunder shear force and the tensile-shear failure occurs oncethe C-shaped tube reaches the limit of bearing capacity
53 Analysis of Bearing Capacity of Supporting MaterialsAnalysis of shear bearing performance it can be seen fromFigure 4(e) that with the increase of shear displacementACC with C-shaped tube on anchor cable has significantlyhigher ability to resist shear deformation than that of the
Vertical load of DS2 100kNVertical load of DS4 150kNVertical load of DS6 200kNVertical load of DS8 250kNVertical load of DS10 300kN
Vertical load of DS1 100kNVertical load of DS5 200kNVertical load of DS9 300kNVertical load of DS2 100kNVertical load of DS6 200kNVertical load of DS10 300kN
Axial load of DS1 100kNAxial load of DS5 200kNAxial load of DS9 300kNAxial load of DS2 100kNAxial load of DS6 200kNAxial load of DS10 300kN
(f )
Figure 4 Data from the double-shear experiment (a) Normal force displacement relationship of anchor cables with the diameter of216mm (b) Axial force displacement relationship of anchor cables with the diameter of 216mm (c) Normal force displacement re-lationship of ACC with the diameter of 216mm (d) Axial force displacement relationship of ACC with the diameter of 216mm (e)Comparison of normal force displacement relationship between anchor cables with the diameter of 216mm and the same type of ACC (f )Comparison of axial force displacement relationship between the anchor cables with the diameter of 216mm and the same type of ACC
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
decisive role in supporting effect and proposed a highprestress and high strength supporting system whichachieved good results in many work sites [19ndash21] Most ofthese technologies and materials aim at controlling the largeaxial deformation of surrounding rock but seldom considerthe transverse loading of supporting materials In order tosolve the contradiction that the supporting material in freesection is easy to break and the transverse bearing capacityand transverse displacement of the supporting material areeasy to decrease due to high prestress [11ndash13] a supportingstructure named Anchor Cable and C-Shaped Tube wasinvented to solve the problem that the anchor cable withhigh prestress in free section is easy to shear and break (eshear mechanical properties of the supporting structurenamed Anchor Cable and C-Shaped Tube were studied bydouble-shear tests in laboratory In this provision AnchorCable and C-Shaped Tube shall hereafter be referred to asACC
2 Brief Introduction of ACC and Analysis ofIts Mechanism
21 Brief Introduction of ACC Supporting Structure ACCconsists of two parts anchor cable with high prestress andC-shaped tube Figure 1 shows the physical drawing andschematic of ACC (e anchor cable with high prestressexerts axial compression force on the structural plane ofsurrounding rock by prestress which increases the frictionbetween joint planes prevents the surrounding rock fromdislocation on both sides of the structural plane togetherwith the dowelling function of anchor cable itself andprevents the surrounding rock from axial shearing dislo-cation (e C-shaped tube is installed at the free end of thestructure which separates the exposed part of anchor cableor rock bolt from surrounding rock [22] When sheardislocation occurs in surrounding rock it would be sepa-rated from the free end of anchor cable or rock boltWith theshear deformation of the structural plane the C-shaped tubeshrinks gradually to completely wrap the anchor cable thusimproving the shear stiffness and increasing the shear ca-pacity of the free end of the supporting structure
22 Analysis of the Mechanism of ACC After ACC is sub-jected to shear force the shear part of slotted steel tubeshrinks continuously and wraps the internal anchor cable(Figure 1(b)) When the free section of anchor cable bearsshear force it is restrained by locks and anchoring section atboth ends At this time it could be seen as the simplysupported beam under concentrated force Assuming thatthe concentrated force acts in the middle of the simplysupported beam and the length of the free section of anchorcable is l (m) according to the relevant formulas of materialmechanics the stress situation of anchor cable at the shearplane in elastic stage can be deduced as follows [23]
M FSl
4 (1)
σ 32M
πD2 + σ1
8FSl
πD2 + σ1 (2)
τ FS πR
221113872 1113873(4R3π)
Iz2R
FS πR221113872 1113873(4R3π)
πR441113872 11138732R
4FS
3A
(3)
It can be seen from formula (2) that when the shear forceis fixed the tensile stress on the anchor cable decreases withthe increase of its diameter After installing the slotted steeltube when it shrinks and deforms the shear force acts 0 kNon the anchor cable due to its certain bearing capacity Itindicates that ACC can absorb a certain shear load to protectthe anchor cable and its limit is Fs1 (kN) It can be seen fromformula (4) that the contracting stiffness of slotted steel tubeK (kNm) could be obtained by experiment When theslotted steel tube and anchor cable form the bearingstructure the diameter of the supporting material is in-creased and the additional axial force is reduced [23]
FS1 KZ 2K R2 minus R2prime( 1113857 (4)
It can be seen from formula (3) that the shear stress ofanchor cable decreases with the increase of cross-sectionalarea which of the whole supporting structure increases dueto the installation of slotted steel tube so ACC bears lessshear stress on the shear plane under the same shear force
M is the bending moment (Nmiddotm) of the anchor cable onthe shear plane FS is the shear load (N) on the anchor cableσ1 is the initial axial stress (Nm2) caused by prestress ofanchor cable and D (m) is the diameter of anchor cable τisthe shear stress (Nm2) of the anchor cable on the shearplaneIz is the moment of inertia relative to the neutral axis(m4) R1 (m) is the inner diameter of slotted steel pipe beforeshrinkage R2 (m) is the outer diameter the inner diameterafter shrinkage is R1prime (m) and the outer diameter is R2prime (m)
3 Brief Introduction of Double-Shear Instrument
(e schematic diagram and physical drawing of the self-designed and developed double-shear test system-tensionand shear system of Anchor Cable (bolt) and C-shaped Tubeare shown in Figure 2 In this system the anchor cable istensioned by locks in the same way as in the work site toprovide prestress to the supporting materials (emaximumaxial tensile load is 120 tons and it equips a vertical loadingsystem with a maximum vertical load of 600 tons in themiddle (is system can apply shear force to the supportingmaterials and the maximum shear displacement is 250mm
(e test samples are 3 concrete specimens of the samesize 300mmtimes 300mmtimes 300mm with 32mm prefabricated
2 Shock and Vibration
holes in the middle in which the supporting materials areinstalled for further tests (e test samples are restrained bythree independent stainless steel shear boxes (Figure 2) andthe shear boxes on both sides are restrained respectively by
four beams and four screws It can be seen from theschematic diagram in Figure 2(a) that the instrument has noforce on the prefabricated joint plane but pure shear force sothe smooth joint plane is what the experiment studies
Vertical loading system
Normal force
The lock of theanchor cable
Concrete test block
Beams for fixing
Axial force
Supporting materials
The base
Screws for fixing
Precast joint surface Shear boxLoading end of
horizontal tensionsystem
Fixed end ofhorizontal stretching
system
(a)
Beam forfixing
Screw for fixing Precast joint surfaces
Loading end ofhorizontal tension
system
Fixed end ofhorizontalstretching
system Shear box
(b)
Figure 2 Sketch map of tension and shear system of Anchor Cable (bolt) and C-shaped Tube (a) Diagram of instrument (b) Physicaldrawing of the instrument
C-shaped tube Anchor cableSupport plate
Anchor
(a)
Before the load After the load
Fs Fs
Z
R2 R
2 prime
R 1 R 1prime
(b)
Figure 1 Physical drawing and schematic of ACC (a) Physical drawing of the ACC (b) Schematic diagram of action form of ACC
Shock and Vibration 3
4 Test Design and Preparation
In this experiment double-shear tests were carried out onanchor cables with the diameter of 216mm and the sametype of ACCs in order to study the influence of differentprestress on the shear performance of anchor cable andanalyze the effect of ACC supporting structure on the shearmechanical properties of anchor cables after the addition ofC-shaped tube into ACC supporting structure Table 1 is thetest design table for this experiment (e specification ofconcrete specimen used in the test was300mmtimes 300mmtimes 300mm and the ratio of water cementsand gravel was 1 2 4 4 After pouring the specimen a100mmtimes 100mm small specimen was left for uniaxialcompression test to determine the uniaxial compressivestrength of the large specimen which is shown in Table 1(e uniaxial compressive strength of the test block wasdetermined as 30MPa according to the results of uniaxialcompression test and some test blocks are shown inFigure 3
5 Analysis of Test Results
(e test results are plotted in Figure 4 and summarized inTable 2 after the experiment Due to a certain gap betweenthe test block and the shear box there will be a stage wherethe shear displacement increases while the shear force re-mains unchanged during the test and the effective sheardisplacement in the table refers to the shear displacementwithout this initial stage of the test
51 Breaking Law of SupportingMaterials (e breaking lawof the anchor cables with the diameter of 216mm in double-shear test is as follows It can be seen from Figures 4(a) and4(b) that it is not the same for the law between the curves ofshear force-shear displacement and axial force-shear dis-placement (e shear force-shear displacement curve isdivided into three stages elastic stage (Figure 4(a) A) shortshear yield stage (Figure 4(a) B) and fracture stage(Figure 4(a) C) (e axial force has a relaxation stage(Figure 4(b)A) with the increase of shear displacement(isrelaxation phenomenon is more common with the increaseof prestress of anchor cable (e reason for the relaxationstage is that a part of the prestress will be transformed intoresistance to the deformation of joint surface in the initialstage of shear deformation and then it will enter the elasticstage (Figure 4(b) B) followed by the long plasticstrengthening stage (Figure 4(b) C) and finally break(Figure 4(b) D)
(e breaking law of ACC of the anchor cables with thediameter of 216mm in double-shear test is as follows
As can be seen from Figures 4(c) and 4(d) the rela-tionship between the shear force-shear displacement curvesof ACC has gone through four stages Stage A is stiffnessstrengthening stage (Figure 4(c) A) Stage B is elastic stage(Figure 4(c) B) Stage C is shear yield stage (Figure 4(c) C)Stage D is fracture stage (Figure 4(c) D) and the four stagesare same for the axial force and anchor cable shown in
Figure 4(d) In the stage a of shear force-shear displacementcurve when ACC is under shear load the slotted steel pipecan shrink with the increase of shear displacement to wrapthe anchor cable so that the slotted steel pipe and the anchorcable can bear the load together which improves the initialshear stiffness of the support material
52Analysis ofMaterialFailureMode Breaking the concreteafter experiment it is required to analyze the failure mode ofsupporting material and concrete blocks Figure 5 showssome representative blocks and supporting materials afterdemolition Figures 5(a) and 5(b) correspond to the testnumber DS3 and Figures 5(c) and 5(d) to the test numberDS8 which are the double-shear test breaking diagrams ofanchor cables with the diameter of 216mm and the sametype of ACC under the prestress of 200 kN
(e failure mode of concrete block is as followsIt can be seen from Figures 5(a) and 5(c) that in the
process of double-shear test severe plastic compressionfailure occurs at the lower part of the shear plane near thejoint surface of the left and right concrete blocks and theupper part of the shear plane on the left and right sides of theintermediate block which result from directly being affectedby supportingmaterial and it becomes a cone-shaped failureplane
During the double-shear test the intermediate block iscontinuously subjected to the reaction force of supportingmaterial Plastic deformation occurs continuously on con-crete blocks until the whole block splits from parallel drillingdirection because the stiffness of it is lower than that of thesupporting material However due to the limitation of theshear box the test block can still apply the load on thesupporting material the test block continues to expand andthe crack continues to expand until the supporting materialis broken
Crack propagation mode of the test block indicates thatthe cracks of the concrete block are radial after the double-shear test of the anchor cables with the diameter of 216mmwhile those of the concrete block of the ACC of anchorcables with the diameter of 216mm are split (is is becausethe anchor cable is structured by many steel strands whichmakes uneven reaction force on the surrounding rock andincreases the possibility of stress concentration Howeverthe C-shaped tube of ACC is circular which can reduce thedegree of stress concentration and the damage to sur-rounding rock
(e failure mode of supporting materials is as followsIt can be seen from Figures 5(b) and 5(d) that the
supporting material presents with the shape of spreadingwing after being sheared and is broken near the shear plane(rough the analysis of the fracture of two kinds of sup-porting materials it is found that there is obvious neckingphenomenon in the fracture of two kinds of anchor cablesand the anchor cables are tensile fracture ACC is protectedby slotted steel pipe When subjected to shear force theC-shaped tube near the shear plane shrinks to wrap theanchor cable and bear the load together with the anchorcable When anchor cables break successively inside there
4 Shock and Vibration
Table 1 Double-shear test schedule
Number Material type Prestress (kN) Average uniaxial compressive strength of specimen (MPa)DS1 Anchor cables with the diameter of 216mm 100 31DS2 ACC with the diameter of 216mm 100 28DS3 Anchor cables with the diameter of 216mm 150 32DS4 ACC with the diameter of 216mm 150 30DS5 Anchor cables with the diameter of 216mm 200 33DS6 ACC with the diameter of 216mm 200 33DS7 Anchor cables with the diameter of 216mm 250 32DS8 ACC with the diameter of 216mm 250 32DS9 Anchor cables with the diameter of 216mm 300 31DS10 ACC with the diameter of 216mm 300 31
Small concretestandard test block
A reserved holewith a diameter of
32mm
Large concretestandard test block
Figure 3 Part of the test blocks
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
A
B
Load
(kN
)
Vertical displacement (mm)
Vertical load of DS1 100kNVertical load of DS2 150kNVertical load of DS3 200kNVertical load of DS4 250kNVertical load of DS5 300kN
C
(a)
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
DA B
Load
(kN
)
Vertical displacement (mm)
Axial load of DS1 100kNAxial load of DS2 150kNAxial load of DS3 200kNAxial load of DS4 250kNAxial load of DS5 300kN
C
(b)
Figure 4 Continued
Shock and Vibration 5
are no steel strands supporting on one side of the internalC-shaped tube But at this time it has been locked by theexpanded rock sample to bear both shear and tension forceunder shear force and the tensile-shear failure occurs oncethe C-shaped tube reaches the limit of bearing capacity
53 Analysis of Bearing Capacity of Supporting MaterialsAnalysis of shear bearing performance it can be seen fromFigure 4(e) that with the increase of shear displacementACC with C-shaped tube on anchor cable has significantlyhigher ability to resist shear deformation than that of the
Vertical load of DS2 100kNVertical load of DS4 150kNVertical load of DS6 200kNVertical load of DS8 250kNVertical load of DS10 300kN
Vertical load of DS1 100kNVertical load of DS5 200kNVertical load of DS9 300kNVertical load of DS2 100kNVertical load of DS6 200kNVertical load of DS10 300kN
Axial load of DS1 100kNAxial load of DS5 200kNAxial load of DS9 300kNAxial load of DS2 100kNAxial load of DS6 200kNAxial load of DS10 300kN
(f )
Figure 4 Data from the double-shear experiment (a) Normal force displacement relationship of anchor cables with the diameter of216mm (b) Axial force displacement relationship of anchor cables with the diameter of 216mm (c) Normal force displacement re-lationship of ACC with the diameter of 216mm (d) Axial force displacement relationship of ACC with the diameter of 216mm (e)Comparison of normal force displacement relationship between anchor cables with the diameter of 216mm and the same type of ACC (f )Comparison of axial force displacement relationship between the anchor cables with the diameter of 216mm and the same type of ACC
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
holes in the middle in which the supporting materials areinstalled for further tests (e test samples are restrained bythree independent stainless steel shear boxes (Figure 2) andthe shear boxes on both sides are restrained respectively by
four beams and four screws It can be seen from theschematic diagram in Figure 2(a) that the instrument has noforce on the prefabricated joint plane but pure shear force sothe smooth joint plane is what the experiment studies
Vertical loading system
Normal force
The lock of theanchor cable
Concrete test block
Beams for fixing
Axial force
Supporting materials
The base
Screws for fixing
Precast joint surface Shear boxLoading end of
horizontal tensionsystem
Fixed end ofhorizontal stretching
system
(a)
Beam forfixing
Screw for fixing Precast joint surfaces
Loading end ofhorizontal tension
system
Fixed end ofhorizontalstretching
system Shear box
(b)
Figure 2 Sketch map of tension and shear system of Anchor Cable (bolt) and C-shaped Tube (a) Diagram of instrument (b) Physicaldrawing of the instrument
C-shaped tube Anchor cableSupport plate
Anchor
(a)
Before the load After the load
Fs Fs
Z
R2 R
2 prime
R 1 R 1prime
(b)
Figure 1 Physical drawing and schematic of ACC (a) Physical drawing of the ACC (b) Schematic diagram of action form of ACC
Shock and Vibration 3
4 Test Design and Preparation
In this experiment double-shear tests were carried out onanchor cables with the diameter of 216mm and the sametype of ACCs in order to study the influence of differentprestress on the shear performance of anchor cable andanalyze the effect of ACC supporting structure on the shearmechanical properties of anchor cables after the addition ofC-shaped tube into ACC supporting structure Table 1 is thetest design table for this experiment (e specification ofconcrete specimen used in the test was300mmtimes 300mmtimes 300mm and the ratio of water cementsand gravel was 1 2 4 4 After pouring the specimen a100mmtimes 100mm small specimen was left for uniaxialcompression test to determine the uniaxial compressivestrength of the large specimen which is shown in Table 1(e uniaxial compressive strength of the test block wasdetermined as 30MPa according to the results of uniaxialcompression test and some test blocks are shown inFigure 3
5 Analysis of Test Results
(e test results are plotted in Figure 4 and summarized inTable 2 after the experiment Due to a certain gap betweenthe test block and the shear box there will be a stage wherethe shear displacement increases while the shear force re-mains unchanged during the test and the effective sheardisplacement in the table refers to the shear displacementwithout this initial stage of the test
51 Breaking Law of SupportingMaterials (e breaking lawof the anchor cables with the diameter of 216mm in double-shear test is as follows It can be seen from Figures 4(a) and4(b) that it is not the same for the law between the curves ofshear force-shear displacement and axial force-shear dis-placement (e shear force-shear displacement curve isdivided into three stages elastic stage (Figure 4(a) A) shortshear yield stage (Figure 4(a) B) and fracture stage(Figure 4(a) C) (e axial force has a relaxation stage(Figure 4(b)A) with the increase of shear displacement(isrelaxation phenomenon is more common with the increaseof prestress of anchor cable (e reason for the relaxationstage is that a part of the prestress will be transformed intoresistance to the deformation of joint surface in the initialstage of shear deformation and then it will enter the elasticstage (Figure 4(b) B) followed by the long plasticstrengthening stage (Figure 4(b) C) and finally break(Figure 4(b) D)
(e breaking law of ACC of the anchor cables with thediameter of 216mm in double-shear test is as follows
As can be seen from Figures 4(c) and 4(d) the rela-tionship between the shear force-shear displacement curvesof ACC has gone through four stages Stage A is stiffnessstrengthening stage (Figure 4(c) A) Stage B is elastic stage(Figure 4(c) B) Stage C is shear yield stage (Figure 4(c) C)Stage D is fracture stage (Figure 4(c) D) and the four stagesare same for the axial force and anchor cable shown in
Figure 4(d) In the stage a of shear force-shear displacementcurve when ACC is under shear load the slotted steel pipecan shrink with the increase of shear displacement to wrapthe anchor cable so that the slotted steel pipe and the anchorcable can bear the load together which improves the initialshear stiffness of the support material
52Analysis ofMaterialFailureMode Breaking the concreteafter experiment it is required to analyze the failure mode ofsupporting material and concrete blocks Figure 5 showssome representative blocks and supporting materials afterdemolition Figures 5(a) and 5(b) correspond to the testnumber DS3 and Figures 5(c) and 5(d) to the test numberDS8 which are the double-shear test breaking diagrams ofanchor cables with the diameter of 216mm and the sametype of ACC under the prestress of 200 kN
(e failure mode of concrete block is as followsIt can be seen from Figures 5(a) and 5(c) that in the
process of double-shear test severe plastic compressionfailure occurs at the lower part of the shear plane near thejoint surface of the left and right concrete blocks and theupper part of the shear plane on the left and right sides of theintermediate block which result from directly being affectedby supportingmaterial and it becomes a cone-shaped failureplane
During the double-shear test the intermediate block iscontinuously subjected to the reaction force of supportingmaterial Plastic deformation occurs continuously on con-crete blocks until the whole block splits from parallel drillingdirection because the stiffness of it is lower than that of thesupporting material However due to the limitation of theshear box the test block can still apply the load on thesupporting material the test block continues to expand andthe crack continues to expand until the supporting materialis broken
Crack propagation mode of the test block indicates thatthe cracks of the concrete block are radial after the double-shear test of the anchor cables with the diameter of 216mmwhile those of the concrete block of the ACC of anchorcables with the diameter of 216mm are split (is is becausethe anchor cable is structured by many steel strands whichmakes uneven reaction force on the surrounding rock andincreases the possibility of stress concentration Howeverthe C-shaped tube of ACC is circular which can reduce thedegree of stress concentration and the damage to sur-rounding rock
(e failure mode of supporting materials is as followsIt can be seen from Figures 5(b) and 5(d) that the
supporting material presents with the shape of spreadingwing after being sheared and is broken near the shear plane(rough the analysis of the fracture of two kinds of sup-porting materials it is found that there is obvious neckingphenomenon in the fracture of two kinds of anchor cablesand the anchor cables are tensile fracture ACC is protectedby slotted steel pipe When subjected to shear force theC-shaped tube near the shear plane shrinks to wrap theanchor cable and bear the load together with the anchorcable When anchor cables break successively inside there
4 Shock and Vibration
Table 1 Double-shear test schedule
Number Material type Prestress (kN) Average uniaxial compressive strength of specimen (MPa)DS1 Anchor cables with the diameter of 216mm 100 31DS2 ACC with the diameter of 216mm 100 28DS3 Anchor cables with the diameter of 216mm 150 32DS4 ACC with the diameter of 216mm 150 30DS5 Anchor cables with the diameter of 216mm 200 33DS6 ACC with the diameter of 216mm 200 33DS7 Anchor cables with the diameter of 216mm 250 32DS8 ACC with the diameter of 216mm 250 32DS9 Anchor cables with the diameter of 216mm 300 31DS10 ACC with the diameter of 216mm 300 31
Small concretestandard test block
A reserved holewith a diameter of
32mm
Large concretestandard test block
Figure 3 Part of the test blocks
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
A
B
Load
(kN
)
Vertical displacement (mm)
Vertical load of DS1 100kNVertical load of DS2 150kNVertical load of DS3 200kNVertical load of DS4 250kNVertical load of DS5 300kN
C
(a)
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
DA B
Load
(kN
)
Vertical displacement (mm)
Axial load of DS1 100kNAxial load of DS2 150kNAxial load of DS3 200kNAxial load of DS4 250kNAxial load of DS5 300kN
C
(b)
Figure 4 Continued
Shock and Vibration 5
are no steel strands supporting on one side of the internalC-shaped tube But at this time it has been locked by theexpanded rock sample to bear both shear and tension forceunder shear force and the tensile-shear failure occurs oncethe C-shaped tube reaches the limit of bearing capacity
53 Analysis of Bearing Capacity of Supporting MaterialsAnalysis of shear bearing performance it can be seen fromFigure 4(e) that with the increase of shear displacementACC with C-shaped tube on anchor cable has significantlyhigher ability to resist shear deformation than that of the
Vertical load of DS2 100kNVertical load of DS4 150kNVertical load of DS6 200kNVertical load of DS8 250kNVertical load of DS10 300kN
Vertical load of DS1 100kNVertical load of DS5 200kNVertical load of DS9 300kNVertical load of DS2 100kNVertical load of DS6 200kNVertical load of DS10 300kN
Axial load of DS1 100kNAxial load of DS5 200kNAxial load of DS9 300kNAxial load of DS2 100kNAxial load of DS6 200kNAxial load of DS10 300kN
(f )
Figure 4 Data from the double-shear experiment (a) Normal force displacement relationship of anchor cables with the diameter of216mm (b) Axial force displacement relationship of anchor cables with the diameter of 216mm (c) Normal force displacement re-lationship of ACC with the diameter of 216mm (d) Axial force displacement relationship of ACC with the diameter of 216mm (e)Comparison of normal force displacement relationship between anchor cables with the diameter of 216mm and the same type of ACC (f )Comparison of axial force displacement relationship between the anchor cables with the diameter of 216mm and the same type of ACC
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
4 Test Design and Preparation
In this experiment double-shear tests were carried out onanchor cables with the diameter of 216mm and the sametype of ACCs in order to study the influence of differentprestress on the shear performance of anchor cable andanalyze the effect of ACC supporting structure on the shearmechanical properties of anchor cables after the addition ofC-shaped tube into ACC supporting structure Table 1 is thetest design table for this experiment (e specification ofconcrete specimen used in the test was300mmtimes 300mmtimes 300mm and the ratio of water cementsand gravel was 1 2 4 4 After pouring the specimen a100mmtimes 100mm small specimen was left for uniaxialcompression test to determine the uniaxial compressivestrength of the large specimen which is shown in Table 1(e uniaxial compressive strength of the test block wasdetermined as 30MPa according to the results of uniaxialcompression test and some test blocks are shown inFigure 3
5 Analysis of Test Results
(e test results are plotted in Figure 4 and summarized inTable 2 after the experiment Due to a certain gap betweenthe test block and the shear box there will be a stage wherethe shear displacement increases while the shear force re-mains unchanged during the test and the effective sheardisplacement in the table refers to the shear displacementwithout this initial stage of the test
51 Breaking Law of SupportingMaterials (e breaking lawof the anchor cables with the diameter of 216mm in double-shear test is as follows It can be seen from Figures 4(a) and4(b) that it is not the same for the law between the curves ofshear force-shear displacement and axial force-shear dis-placement (e shear force-shear displacement curve isdivided into three stages elastic stage (Figure 4(a) A) shortshear yield stage (Figure 4(a) B) and fracture stage(Figure 4(a) C) (e axial force has a relaxation stage(Figure 4(b)A) with the increase of shear displacement(isrelaxation phenomenon is more common with the increaseof prestress of anchor cable (e reason for the relaxationstage is that a part of the prestress will be transformed intoresistance to the deformation of joint surface in the initialstage of shear deformation and then it will enter the elasticstage (Figure 4(b) B) followed by the long plasticstrengthening stage (Figure 4(b) C) and finally break(Figure 4(b) D)
(e breaking law of ACC of the anchor cables with thediameter of 216mm in double-shear test is as follows
As can be seen from Figures 4(c) and 4(d) the rela-tionship between the shear force-shear displacement curvesof ACC has gone through four stages Stage A is stiffnessstrengthening stage (Figure 4(c) A) Stage B is elastic stage(Figure 4(c) B) Stage C is shear yield stage (Figure 4(c) C)Stage D is fracture stage (Figure 4(c) D) and the four stagesare same for the axial force and anchor cable shown in
Figure 4(d) In the stage a of shear force-shear displacementcurve when ACC is under shear load the slotted steel pipecan shrink with the increase of shear displacement to wrapthe anchor cable so that the slotted steel pipe and the anchorcable can bear the load together which improves the initialshear stiffness of the support material
52Analysis ofMaterialFailureMode Breaking the concreteafter experiment it is required to analyze the failure mode ofsupporting material and concrete blocks Figure 5 showssome representative blocks and supporting materials afterdemolition Figures 5(a) and 5(b) correspond to the testnumber DS3 and Figures 5(c) and 5(d) to the test numberDS8 which are the double-shear test breaking diagrams ofanchor cables with the diameter of 216mm and the sametype of ACC under the prestress of 200 kN
(e failure mode of concrete block is as followsIt can be seen from Figures 5(a) and 5(c) that in the
process of double-shear test severe plastic compressionfailure occurs at the lower part of the shear plane near thejoint surface of the left and right concrete blocks and theupper part of the shear plane on the left and right sides of theintermediate block which result from directly being affectedby supportingmaterial and it becomes a cone-shaped failureplane
During the double-shear test the intermediate block iscontinuously subjected to the reaction force of supportingmaterial Plastic deformation occurs continuously on con-crete blocks until the whole block splits from parallel drillingdirection because the stiffness of it is lower than that of thesupporting material However due to the limitation of theshear box the test block can still apply the load on thesupporting material the test block continues to expand andthe crack continues to expand until the supporting materialis broken
Crack propagation mode of the test block indicates thatthe cracks of the concrete block are radial after the double-shear test of the anchor cables with the diameter of 216mmwhile those of the concrete block of the ACC of anchorcables with the diameter of 216mm are split (is is becausethe anchor cable is structured by many steel strands whichmakes uneven reaction force on the surrounding rock andincreases the possibility of stress concentration Howeverthe C-shaped tube of ACC is circular which can reduce thedegree of stress concentration and the damage to sur-rounding rock
(e failure mode of supporting materials is as followsIt can be seen from Figures 5(b) and 5(d) that the
supporting material presents with the shape of spreadingwing after being sheared and is broken near the shear plane(rough the analysis of the fracture of two kinds of sup-porting materials it is found that there is obvious neckingphenomenon in the fracture of two kinds of anchor cablesand the anchor cables are tensile fracture ACC is protectedby slotted steel pipe When subjected to shear force theC-shaped tube near the shear plane shrinks to wrap theanchor cable and bear the load together with the anchorcable When anchor cables break successively inside there
4 Shock and Vibration
Table 1 Double-shear test schedule
Number Material type Prestress (kN) Average uniaxial compressive strength of specimen (MPa)DS1 Anchor cables with the diameter of 216mm 100 31DS2 ACC with the diameter of 216mm 100 28DS3 Anchor cables with the diameter of 216mm 150 32DS4 ACC with the diameter of 216mm 150 30DS5 Anchor cables with the diameter of 216mm 200 33DS6 ACC with the diameter of 216mm 200 33DS7 Anchor cables with the diameter of 216mm 250 32DS8 ACC with the diameter of 216mm 250 32DS9 Anchor cables with the diameter of 216mm 300 31DS10 ACC with the diameter of 216mm 300 31
Small concretestandard test block
A reserved holewith a diameter of
32mm
Large concretestandard test block
Figure 3 Part of the test blocks
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
A
B
Load
(kN
)
Vertical displacement (mm)
Vertical load of DS1 100kNVertical load of DS2 150kNVertical load of DS3 200kNVertical load of DS4 250kNVertical load of DS5 300kN
C
(a)
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
DA B
Load
(kN
)
Vertical displacement (mm)
Axial load of DS1 100kNAxial load of DS2 150kNAxial load of DS3 200kNAxial load of DS4 250kNAxial load of DS5 300kN
C
(b)
Figure 4 Continued
Shock and Vibration 5
are no steel strands supporting on one side of the internalC-shaped tube But at this time it has been locked by theexpanded rock sample to bear both shear and tension forceunder shear force and the tensile-shear failure occurs oncethe C-shaped tube reaches the limit of bearing capacity
53 Analysis of Bearing Capacity of Supporting MaterialsAnalysis of shear bearing performance it can be seen fromFigure 4(e) that with the increase of shear displacementACC with C-shaped tube on anchor cable has significantlyhigher ability to resist shear deformation than that of the
Vertical load of DS2 100kNVertical load of DS4 150kNVertical load of DS6 200kNVertical load of DS8 250kNVertical load of DS10 300kN
Vertical load of DS1 100kNVertical load of DS5 200kNVertical load of DS9 300kNVertical load of DS2 100kNVertical load of DS6 200kNVertical load of DS10 300kN
Axial load of DS1 100kNAxial load of DS5 200kNAxial load of DS9 300kNAxial load of DS2 100kNAxial load of DS6 200kNAxial load of DS10 300kN
(f )
Figure 4 Data from the double-shear experiment (a) Normal force displacement relationship of anchor cables with the diameter of216mm (b) Axial force displacement relationship of anchor cables with the diameter of 216mm (c) Normal force displacement re-lationship of ACC with the diameter of 216mm (d) Axial force displacement relationship of ACC with the diameter of 216mm (e)Comparison of normal force displacement relationship between anchor cables with the diameter of 216mm and the same type of ACC (f )Comparison of axial force displacement relationship between the anchor cables with the diameter of 216mm and the same type of ACC
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
Table 1 Double-shear test schedule
Number Material type Prestress (kN) Average uniaxial compressive strength of specimen (MPa)DS1 Anchor cables with the diameter of 216mm 100 31DS2 ACC with the diameter of 216mm 100 28DS3 Anchor cables with the diameter of 216mm 150 32DS4 ACC with the diameter of 216mm 150 30DS5 Anchor cables with the diameter of 216mm 200 33DS6 ACC with the diameter of 216mm 200 33DS7 Anchor cables with the diameter of 216mm 250 32DS8 ACC with the diameter of 216mm 250 32DS9 Anchor cables with the diameter of 216mm 300 31DS10 ACC with the diameter of 216mm 300 31
Small concretestandard test block
A reserved holewith a diameter of
32mm
Large concretestandard test block
Figure 3 Part of the test blocks
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
A
B
Load
(kN
)
Vertical displacement (mm)
Vertical load of DS1 100kNVertical load of DS2 150kNVertical load of DS3 200kNVertical load of DS4 250kNVertical load of DS5 300kN
C
(a)
0 10 20 30 40 50 60 70 80 90 100 110 120
50100150200250300350400450500550600650
DA B
Load
(kN
)
Vertical displacement (mm)
Axial load of DS1 100kNAxial load of DS2 150kNAxial load of DS3 200kNAxial load of DS4 250kNAxial load of DS5 300kN
C
(b)
Figure 4 Continued
Shock and Vibration 5
are no steel strands supporting on one side of the internalC-shaped tube But at this time it has been locked by theexpanded rock sample to bear both shear and tension forceunder shear force and the tensile-shear failure occurs oncethe C-shaped tube reaches the limit of bearing capacity
53 Analysis of Bearing Capacity of Supporting MaterialsAnalysis of shear bearing performance it can be seen fromFigure 4(e) that with the increase of shear displacementACC with C-shaped tube on anchor cable has significantlyhigher ability to resist shear deformation than that of the
Vertical load of DS2 100kNVertical load of DS4 150kNVertical load of DS6 200kNVertical load of DS8 250kNVertical load of DS10 300kN
Vertical load of DS1 100kNVertical load of DS5 200kNVertical load of DS9 300kNVertical load of DS2 100kNVertical load of DS6 200kNVertical load of DS10 300kN
Axial load of DS1 100kNAxial load of DS5 200kNAxial load of DS9 300kNAxial load of DS2 100kNAxial load of DS6 200kNAxial load of DS10 300kN
(f )
Figure 4 Data from the double-shear experiment (a) Normal force displacement relationship of anchor cables with the diameter of216mm (b) Axial force displacement relationship of anchor cables with the diameter of 216mm (c) Normal force displacement re-lationship of ACC with the diameter of 216mm (d) Axial force displacement relationship of ACC with the diameter of 216mm (e)Comparison of normal force displacement relationship between anchor cables with the diameter of 216mm and the same type of ACC (f )Comparison of axial force displacement relationship between the anchor cables with the diameter of 216mm and the same type of ACC
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
are no steel strands supporting on one side of the internalC-shaped tube But at this time it has been locked by theexpanded rock sample to bear both shear and tension forceunder shear force and the tensile-shear failure occurs oncethe C-shaped tube reaches the limit of bearing capacity
53 Analysis of Bearing Capacity of Supporting MaterialsAnalysis of shear bearing performance it can be seen fromFigure 4(e) that with the increase of shear displacementACC with C-shaped tube on anchor cable has significantlyhigher ability to resist shear deformation than that of the
Vertical load of DS2 100kNVertical load of DS4 150kNVertical load of DS6 200kNVertical load of DS8 250kNVertical load of DS10 300kN
Vertical load of DS1 100kNVertical load of DS5 200kNVertical load of DS9 300kNVertical load of DS2 100kNVertical load of DS6 200kNVertical load of DS10 300kN
Axial load of DS1 100kNAxial load of DS5 200kNAxial load of DS9 300kNAxial load of DS2 100kNAxial load of DS6 200kNAxial load of DS10 300kN
(f )
Figure 4 Data from the double-shear experiment (a) Normal force displacement relationship of anchor cables with the diameter of216mm (b) Axial force displacement relationship of anchor cables with the diameter of 216mm (c) Normal force displacement re-lationship of ACC with the diameter of 216mm (d) Axial force displacement relationship of ACC with the diameter of 216mm (e)Comparison of normal force displacement relationship between anchor cables with the diameter of 216mm and the same type of ACC (f )Comparison of axial force displacement relationship between the anchor cables with the diameter of 216mm and the same type of ACC
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
same type of anchor cable Under the same shear dis-placement the shear force of anchor cables with differentprestress is generally less than that of ACC and the sheardisplacement of ACC is also larger than that of the same typeof anchor cable when reaching the limit of shear capacity Itshows that ACC can improve the shear stiffness and ultimatebearing capacity of internal anchor cable
(e key data of double-shear test are listed in Table 2Figure 6(a) shows the shear capacity and shear displacementat ultimate shear capacity of anchor cables with the diameterof 216mm with the increase of prestress under the sameconditions It can be seen from Table 2 and Figure 6(a) thatwith the increase of preload the shear bearing capacity of theanchor cable has a downward trend while the shear dis-placement is not significantly affected
Figure 6(b) shows the shear capacity and shear dis-placement of ACC with the diameter of 216mm with theincrease of prestress under the same conditions It can beseen from the figure that when the C-shaped tube becomessupporting structure of ACC the shear bearing capacity isgreatly improved and its shear capacity has been greatlyincreased by at least 305 Compared with the anchorcables with the diameter of 216mm the shear displacement
also increases to a certain extent with the minimum in-creasing by 71 and the maximum by 299
By comparing the two types of data it can be seen thatthe ACC supporting structure improves the shear bearingcapacity of the internal anchor cable and after using theACC supporting structure it can have a stronger ability toresist shear deformation
In the analysis of axial bearing capacity it can be seenfrom Figure 4(f ) that when it reaches the ultimate shearcapacity the value of ultimate axial bearing capacity of boththe anchor cable and ACC is close namely the greater theprestress the slower the growth rate of axial force with theincrease of shear displacement but ultimately it reaches thetensile yield load with similar numerical value According tothe statistical data in Table 2 compared with the anchorcable the ultimate tensile load of ACC supporting structurehas been slightly optimized with the maximum optimiza-tion rate of 96 and the minimum of 49
Above all the ultimate shear capacity of the anchor cableis negatively correlated with the prestress Under the sameprestress ACC can enhance the shear stiffness of the internalanchor cable and the resistance of shear deformation with alifting rate of more than 71 it can also increase the
Right precast joint plane
e
Left precast joint plane
(c)
Tensile failure
Tension shear failure
(d)
Figure 5 Display of material failure forms (a) Failure diagram of anchor cables with the diameter of 216mm test block (b) Schematicdiagram of breaking of anchor cables with the diameter of 216mm (c) Failure diagram of ACC with the diameter of 216mm test block (d)Fracture diagram of ACC with the diameter of 216mm
8 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
ultimate shear capacity of the internal anchor cable with alifting rate of more than 305 ACC can improve the axialbearing capacity of the inner cable by a small margin whichis more than 49
6 Conclusion
(rough the double-shear test of the prestressed anchorcable with diameter of 216mm and ACC supportingstructure of the same type the following conclusions areobtained
(1) (ere is a negative correlation between the ultimateshear capacity of anchor cable and its prestress (egreater the pretension the weaker the shear capacity(erefore the shear bearing capacity of the freesection of the prestressed anchor cable will be re-duced when the high pretightening force is appliedand there is a risk of shear fracture
(2) (rough the analysis of the failure mode of sur-rounding rock on both sides of joint surface it isfound that the stress concentration of ordinary an-chor cable will occur in the process of shearing due tothe structure of steel strand itself which will deepenthe damage to the surrounding rock of structuralplane However ACC could alleviate the degree ofstress concentration of the interaction betweensupporting structure and surrounding rock and re-duce the damage to surrounding rock
(3) ACC can improve the shear stiffness and the resis-tance of shear deformation of the internal anchorcable under the same prestress with the lifting rate ofmore than 71 the ultimate shear capacity of theinternal anchor cable can be increased by more than305 and the axial bearing capacity of the internalanchor cable can be slightly improved by more than
49 ACC supporting structure has the ability toeliminate shear fracture of anchor cable with highprestress in free section
Data Availability
(e experimental data were obtained from experimentalequipment independently designed by China University ofMining and Technology in Beijing
Conflicts of Interest
(e authors declare that they have no conflicts of interest
References
[1] X Yang C Hu J Liang et al ldquoA case study on the control oflarge deformations in a roadway located in the dursquoerping coalmine in Chinardquo Advances in Materials Science and Engi-neering vol 2019 Article ID 9628142 13 pages 2019
[2] C Zang M Chen G Zhang K Wang and D Gu ldquoResearchon the failure process and stability control technology in adeep roadway numerical simulation and field testrdquo EnergyScience amp Engineering vol 8 no 7 pp 2297ndash2310 2020
[3] Q Wang B Jiang R Pan et al ldquoFailure mechanism ofsurrounding rock with high stress and confined concretesupport systemrdquo International Journal of Rock Mechanics andMining Sciences vol 102 pp 89ndash100 2018
[4] G U O Zhibiao L Zhang H Wang et al ldquoFailure mech-anism of bolts and countermeasures in swelling soft rocksupportrdquo Tehnicki Vjesnik-Technical Gazette vol 25 no 5pp 1447ndash1456 2018
[5] Y Yu X Wang J Bai L Zhang and H Xia ldquoDeformationmechanism and stability control of roadway surrounding rockwith compound roof research and applicationsrdquo Energiesvol 13 no 6 Article ID 1350 2020
[6] S R Wang Y H Wang J Gong Z L Wang Q X Huangand F L Kong ldquoFailure mechanism and constitutive relation
DS1 DS3 DS5 DS7 DS90
100
200
300
400
500
600
700Fo
rce (
kN)
Test number
Displacement (mm)Force (kN)
(a)
DS1 DS2 DS3 DS4 DS5 DS6 DS7 DS8 DS9 DS100
100
200
300
400
500
600
700
800
900
1000
299253165
413358343363
Forc
e (kN
)
Test number
Displacement (mm)Force (kN)
305
298 71
(b)
Figure 6 Comparison of shear bearing capacity of supporting materials (a) Analysis of shear bearing capacity of the anchor cables with thediameter of 216mm (b) Comparison of bearing capacity between anchor cables with the diameter of 216mm and the same type of ACC
Shock and Vibration 9
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
10 Shock and Vibration
for an anchorage segment of an anchor cable under pull-outloadingrdquo Acta Mechanica vol 231 no 8 pp 3305ndash33172020
[7] A M Ferrero ldquo(e shear strength of reinforced rock jointsrdquoInternational Journal of Rock Mechanics and Mining Sciencesamp Geomechanics Abstracts vol 32 no 6 pp 595ndash605 1995
[8] T Xiao H Li Y Xu et al ldquoFracture mechanism and controlof coal roadway shoulder anchor in deep tectonic stress areardquoGeotechnical Mechanics vol 8 pp 2303ndash2308 2013
[9] X Li N Aziz A Mirzaghorbanali and J Nemcik ldquoBehaviorof fiber glass bolts rock bolts and cable bolts in shearrdquo RockMechanics and Rock Engineering vol 49 no 7 pp 2723ndash2735 2016
[10] Q Liu G Lei and X Peng ldquoResearch progress and thinkingon anchorage mechanism of deep fractured rock massrdquoJournal of Rock Mechanics and Engineering vol 35 no 2pp 312ndash332 2016
[11] R Yang ldquoExperimental study on shear mechanical propertiesof prestressed anchor cablesrdquo Journal of China University ofMining and Technology vol 47 no 6 pp 1166ndash1174 2018
[12] N Aziz H Rasekh A Mirzaghorbanali G YangS Khaleghparast and J Nemcik ldquoAn experimental study onthe shear performance of fully encapsulated cable bolts insingle shear testrdquo Rock Mechanics and Rock Engineeringvol 51 no 7 pp 2207ndash2221 2018
[13] A Mirzaghorbanali H Rasekh N Aziz G YangS Khaleghparast and J Nemcik ldquoShear strength properties ofcable bolts using a new double shear instrument experimentalstudy and numerical simulationrdquo Tunnelling and Under-ground Space Technology vol 70 pp 240ndash253 2017
[14] H Lin Y Zhu J Yang and Z J Wen ldquoAnchor stress anddeformation of the bolted joint under shearingrdquo Advances inCivil Engineering vol 2020 Article ID 3696489 10 pages2020
[15] H Lin X Zhang Y X Wang et al ldquoImproved nonlinearNishihara shear creep model with variable parameters forrock-like materialsrdquo Advances in Civil Engineering vol 2020Article ID 7302141 15 pages 2020
[16] M He W Gong J Wang et al ldquoDevelopment of a novelenergy-absorbing bolt with extraordinarily large elongationand constant resistancerdquo International Journal of Rock Me-chanics and Mining Sciences vol 67 pp 29ndash42 2014
[17] M C He and Z Guo ldquoMechanical property and engineeringapplication of anchor bolt with constant resistance and largedeformationrdquo Chinese Journal of Rock Mechanics and Engi-neering vol 33 pp 1297ndash1308 2014 in Chinese
[18] M C He C Li W Gong et al ldquoSupport principles of NPRboltscables and control techniques of large deformationrdquoChinese Journal of Rock Mechanics and Engineering vol 35pp 1513ndash1529 2016 in Chinese
[19] H Kang J Wang and J Lin ldquoHigh prestressed strong supportsystem and its application in deep roadwayrdquo Acta Coal Sinicavol 12 pp 1233ndash1238 2007
[20] B Hu H P Kang and J Lin ldquoComparison and application ofhigh prestress and intensive support system in close soft andcracked roadway supportrdquo Advanced Materials Researchvol 29 pp 524ndash527 2012
[21] H Kang YWu and F Gao ldquoDeformation characteristics andreinforcement technology for entry subjected to mining-in-duced stressesrdquo Journal of Rock Mechanics and GeotechnicalEngineering vol 3 no 3 pp 207ndash219 2011
[22] R Shan P Huang H Yuan et al ldquoResearch on the full-section anchor cable and C-shaped tube support system of
mining roadway in island coal facesrdquo Journal of Asian Ar-chitecture and Building Engineering p 12 2021
[23] S Yan Mechanics of Materials (e Science PublishingCompany New York NY USA 2012
