Construction of Highway Earthworks - Standards for · PDF fileConstruction of Highway...

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Construction of

Highway

Earthworks

Summary: This advice note gives guidance on the construction of highway earthworkswhere the Specification for Highway Works is being implemented.

THE HIGHWAYS AGENCY HA 70/94

THE SCOTTISH OFFICE DEVELOPMENT DEPARTMENT

THE WELSH OFFICE

Y SWYDDFA GYMREIG

THE DEPARTMENT OF

THE ENVIRONMENT FOR NORTHERN IRELAND

Volume 4 Section 1Part 5 HA 70/94 Registration of Amendments

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REGISTRATION OF AMENDMENTS

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amendments amendments

Volume 4 Section 1Registration of Amendments Part 5 HA 70/94


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REGISTRATION OF AMENDMENTS

Amend Page No Signature & Date of Amend Page No Signature & Date ofNo incorporation of No incorporation of

amendments amendments

DESIGN MANUAL FOR ROADS AND BRIDGES


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VOLUME 4 GEOTECHNICS ANDDRAINAGE

SECTION 1 EARTHWORKS

PART 5

HA 70/94

CONSTRUCTION OF HIGHWAYEARTHWORKS

Contents

Chapter

1. Introduction

2. Testing for Classification and Acceptability

3. Slopes, Blasting and Evacuation

4. Compaction of Earthworks Materials Using theMethod Specification

5. Compaction of Earthworks Materials Using theEnd-Product Specification

6. Landscape Areas

7 Information on Some Specific Materials

8. Effects of Construction Plant Operations

9. Preventing the Spread of Plant and AnimalDiseases

10. Instrumentation and Monitoring

11. Feedback

12. References

13. Enquiries

Appendix AAppendix BAppendix CAppendix D

Volume 4 Section 1 Chapter 1Part 5 HA 70/94 Introduction

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1. INTRODUCTIONGeneral

1.1 The guidance given in this Advice Note hasbeen prepared to meet the needs of the SpecificatioHighway Works (MCHW 1) and its Notes for Guidan(MCHW 2).

Scope

1.2 This guidance is applicable to all trunk roadsand motorway projects and may also be consideredgood practice for other schemes involving majorearthworks. In Northern Ireland, the guidance isapplicable to those roads designated by the OverseeOrganisation.

1.3 This Advice Note is focused on theconstructional aspects of earthworks. Constructionaspects of the widening of highway earthworks arecovered in HA 43 (DMRB 4.1.2). The design andpreparation of Contract documents for earthworks iscovered in HA 44 (DMRB 4.1.1). Advice Note HA 44(DMRB 4.1.1), of necessity, covers designconsiderations relating to the construction of earthwand these have not been repeated here; HA 44 (DM4.1.1) should be consulted when construction practicor methods may affect the design.

Definitions and Abbreviations

1.4 The Conditions of Contract (CoC) are theInstitution of Civil Engineers (ICE) Conditions ofContract (Fifth Edition) for use in connection with CivEngineering Construction works, as amended by theManual of Contract Documents, Volume 0, Section 1Model Contract Document for Highway Contracts.

1.5 In the engineering discipline, the definitions and distinctions between, the terms `soil' and `rock' usually based on measures of particle size and eithehardness, durability, inertness, or any combination othese. The accepted values for these criteria aregoverned by the intended use of the material. Furthermore the use of `soil' or `rock' can haveimplications for administering and costing projects. The result has been a number of different definitionseach appropriate to a specific field of work. The SHappropriately, prefers to use `material' and `classes material' to avoid any confusion of terms. Where theword `rock' is used, in Sub-Clauses 603.5, 603.6 an604.1, it refers to insitu rock or to argillaceous rock a

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is defined for use in selected fills. There is no suchterm as `rock in excavation' in the SHW and forexcavation purposes `Hard Material', as defined in theMMHW, should be assessed from the investigationdrilling rate and type of recovery, insitu tests, trial pitsand exposures. As far as this Advice Note is concerned,rock, soil, or material are used as general engineeringterms and no contractual definition should be inferred. This reflects the differing terminology found inearthworks construction, design, assessment, anddocumentation.

Implementation

1.6 This Advice Note should be used forthwith forall schemes currently being prepared or underconstruction provided that, in the opinion of theOverseeing Organisation this would not result insignificant additional expenses or delay progress. TheDesign Organisation should confirm its application toparticular schemes with the Overseeing Organisation.

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Volume 4 Section 1 Chapter 2Part 5 HA 70/94 Testing for Classification and Acceptability

2. TESTING FOR CLASSIFICATION ANDACCEPTABILITY

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Responsibility for classification

2.1 SHW Appendix 6/1 requires the compiler tostate who classifies and where. It is usuallyrecommended that the Contractor should be givenresponsibility for classification of site won materialsbased on the Designer's limits and criteria. In somecircumstances, however, it may be more appropriatethe Engineer to take this responsibility.

Responsibility for testing

2.2 SA 3 `Testing in highway constructioncontracts' (MCHW 0.3.3) should be consulted fordetails on responsibilities for testing and accreditatioof testing and sampling.

2.3 It is recommended that in general the Engineconducts testing. Where the Contractor is to providethe site testing laboratory for the Engineer's use, theContract shall include at Appendix 1/1 details of allapparatus and equipment required to equip theEngineer's laboratory.

2.4 If the Contractor is given responsibility fortesting, the tests and their frequency should be giventhe Contract. The Engineer shall clearly specify inSHW Appendix 1/5 (based on Table NG 1/1) the typeand minimum frequency of testing to be conducted tosatisfy the design together with the source referenceeach test (British Standard, SHW etc). The test resushould be submitted as required by the Engineer.

2.5 The Contractor has an overall responsibility maintain the nature of acceptable material, irrespectiof who is responsible for testing, so that when it isplaced and compacted it remains acceptable inaccordance with the Contract.

2.6 Testing should be carried out at excavation fmaterials found on site unless the material is likely tochange between excavation and deposition, in whichcase further sampling and testing should be carried oat deposition.

2.7 Imported materials should be sampled andtested for compliance at deposition and preferably alat source. SHW Appendix 6/1 should state thelocations of all compliance sampling and testing


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2.8 SHW Sub-Clause 601.4 allows unacceptablematerial to be processed by mechanical, chemical orother means to render the material acceptable. This wiusually be achieved by reducing the moisture content othe material. The purpose behind this Sub-Clause is tomake maximum use of on-site materials.

2.9 Advice on NAMAS accredited testing is givenin SA 3 (MCHW 0.3.3). In Northern Ireland, NAMASaccredition is not yet a requirement and any testinglaboratory which the Contractor proposes to use will besubject to the approval of the Engineer.


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Volume 4 Section 1 Chapter 3Part 5 HA 70/94 Slopes, Blasting and Excavation

3. SLOPES, BLASTING AND EXCAVATION

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Soil Slopes

3.1 The soil slopes of cuttings and embankmentshould be inspected on construction and subsequenregular intervals for signs of cracking or bulging whicwould indicate imminent failure of the slope, or seepwhich could lead to instability. Instability early in a sslope's life is likely to be deep seated, related to somform of discontinuity such as a pre-existing shear plaor a thin weak clay layer. The consequences are likto be severe and may involve considerable amountsfailed material. Shallow failures, as described by Pe(1989), are relatively rare on new soil slopes whencompared to slopes over, say, ten years old but theyoccur more frequently on steep recently constructedrock fill slopes as a result of topsoil slippage; the failis not of the rock fill itself. Preventative measures insoil and rock slopes will be required in cases where geotechnical investigation shows instability to be like(Perry, 1989; Johnson, 1985). Where failure hasalready begun repair methods will need to be emplo(HA 48 (DMRB 4.1.2); Johnson, 1985). Bothstrengthening and repair works may be the subject oVariation Order subject to the changes being agreedthe Engineer. Instability due to excavation of the toethe slope is covered in SHW Sub-Clause 603.2. Removal of toe restraint in this way can lead to failurof the slope which, in the case of cuttings, results inmaterial moving onto the carriageway or, in the caseembankments, can undercut the pavement leading tmovement and failure of the pavement.

3.2 Proposals for tree planting need carefulconsideration in terms of their effect on slope stabilitparticularly on clay slopes, as well as to ensuresuccessful growth. Tree pits can pond water andconcentrate flows of water into the slope which can lto instability. It is necessary, therefore, to ensure thepositions of pits are such that they do not form a patfor the development of cracking and that water isprevented from ponding within them.

Rock Slopes

3.3 The exposed faces of rock cuttings should binspected for discontinuities especially those orientain such a manner as to lead to instability (Matheson,1983; Hudson, 1989; Hoek and Bray, 1981). The fshould also be examined for signs of excessive



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3.4 Whenever blasting is anticipated, good ply relations and a public information and education

programme by Contractors are essential, both whed blasting commences and during the following

construction period. There needs to be full consultf a with Local Authorities and the police regarding tr by management measures and publicity. The requ of for traffic management measures should include

warning signal procedures.e

3.5 Safety matters should always be conside of The blasting Contractor must be familiar with the

appropriate codes of practice for safety, such as5607 (1988) or equivalent in other states of the

the Contractor shall only permit explosives to be u, or handled by or under the immediate control of a

competent person in accordance with Constructio(General Provisions) Regulations 1961 (Regulati

ad and subsequent amending Regulations. Advice HA 44 (DMRB 4.1.1) gives details of acceptablevibration levels. The use of explosives in Northe

Ireland is governed by the Explosives Regulations1970.

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weathering after a period of exposure, preferablythrough the winter season. If left unchecked, excessivweathering could lead to instability and future highmaintenance costs, incurred as a result of frequentremoval of large amounts of debris from the base of thface. The inspections should be undertaken by anexperienced geotechnical engineer and a reportsubmitted on the stability of the face and whetherremedial action is needed. Proposals for remedialaction need to be agreed by the OverseeingOrganisation. Further details can be found in HA 48(DMRB 4.1.2) Earthworks: Maintenance of highwayearthworks and drainage. Possible remedial measureare outlined in SHW Sub-Clause 603.6.

Blasting

European Economic Area. SHW Clause 607 states th

3.6 SHW Appendix 6/3 includes requirements forblasting and the Engineer's arrangements for theContractor's monitoring of property off-site. The naturand condition of property should be taken into accounAn assessment of the sensitivity of the situation, havinregard to the occupiers of such property, will need to bmade if complaints are received.



Volume 4 Section 1 Chapter 4Part 5 HA 70/94 Compaction of Earthworks Materials Using the Method Specification

4. COMPACTION OF EARTHWORKSMATERIALS USING THE METHODSPECIFICATION

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General

4.1 The SHW method specification defines howcompaction should be conducted in terms of the typeof compaction plant, method of operation of the plantnumber of passes of the plant required and the finalthickness of the compacted layer. Measurements of final state of compaction, that is the in-situ dry densitor air voids (defined in Appendix A) are not normallyrequired.

4.2 The information given in SHW Table 6/4 hasbeen determined from research using full scale testinof the plant described (Parsons, 1992). These trialsignored the effects of any compaction fromearthmoving machinery, so that the figures are, to thaextent, conservative. The values given are forsatisfactory compaction of the more difficult conditionof materials in each group, so that in many instancescompaction may be more than adequate. Thecompactive effort stipulated in SHW Table 6/4 isdesigned to produce an adequate state of compactio(usually 10% air voids or less) at a conservative (lowmoisture content for the particular class of soil (seeSHW NG 612 for more details).

Ensuring compliance with the method specification

4.3 The flow chart in Figure 4.1 illustrates howcompliance with the method specification can beachieved and forms the framework for the followingparagraphs. SHW Sub-Clause 602.2 requires that thhaulage of material to embankments or other areas ofill shall proceed only when sufficient spreading andcompaction plant is operating at the place of depositito ensure compliance with Clause 612 (Compaction ofills).

4.4 SHW Table 6/1 identifies different Classes ofmaterials and prescribes different methods forcompaction. When the method specification is requirand more than one Class of material is being used, itmay not be practicable to define the area where eachClass of material occurs in order to apply the

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appropriate method of compaction. In these cases themethod for the material requiring the greatestcompactive effort shall be used (SHW Sub-Clause612.8).

4.5 The majority of available compaction plant isincluded in SHW Table 6/4. It will be necessary toidentify and classify these machines in order todetermine the thickness of compacted layer and numbof passes to be applied. The general type of machine(smooth-wheeled roller, vibrating roller, vibrating-platecompactor, etc), total mass and distribution of massbetween rolls, must be determined and, in mostinstances, either width of roll, number of wheels, orarea of plate. Direct weighing and measurements arepreferable, although the machine specifications may beresorted to; it is essential that the correct parameters aused. Placing of fill materials must never commenceuntil compaction plant is available. In approving thesimultaneous usage of items of compaction plant ofdifferent types, the least thickness of layer and numberof passes should be in accordance with SHW Sub-Clause 612.10 (xiv).

4.6 SHW Table 6/4 and SHW Sub-Clause 612.10define, stipulate and classify the type of compactionplant to be used with the method specification. The lisof compaction plant is comprehensive. If, however, theContractor wishes to use a piece of construction plantnot given in the SHW Table 6/4, the proposedalternative method must achieve the same state ofcompaction in a site trial as would be achieved usingthe specified method (SHW Sub-Clause 612.6, andAppendix C of this Advice Note).

4.7 Great reliance will have to be placed onearthworks inspectors to ensure compliance ofcompaction undertaken using the method specificationDifficulties will be minimized by ensuring that thecontinuous operation of the compaction machinerywhich the Contractor proposes to use is commensuratewith the rate of fill to be expected from the excavatingand spreading machinery in use. This is achieved bycomparing the estimated output of the compaction plan

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Chapter 4 Volume 4 Section 1Compaction of Earthworks Materials Using the Method Specification Part 5 HA 70/94

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with the estimated rate of input of earthwork materiaand as a result removes the need, under normal worconditions, for inspectors to count the number of pasof compaction plant. Particular attention must be givto ensure that the vibrating mechanism is in operatioall times during compaction.

4.8 In order to estimate the potential output ofcompaction plant, the Engineer's inspectors need to the speed of travel of the compactor when it is operanormally. This can be achieved by timing thecompactor over a measured distance. If the measurspeed exceeds any maximum stipulated, or if a highgear than that stipulated is used (eg with vibratingrollers), the speed should be reduced or the numberpasses to be applied should be increased in proportito the increase in speed beyond the maximum speciIt is not a requirement of the SHW that a speedrestriction be applied to compactors other than vibrarollers or vibrating-plate compactors, however it musbe measured in order to determine potential output, hence compliance. The potential output of thecompactor or a team of compactors can be determinfrom the following:

Where P = output of a machine (m /hr)3

W = effective width (90% of widthof rolls to allow for overlap)(m)

V = speed of travel (km/hr)D = depth of layer required in the

specification (mm)N = number of passes required in

the specification.

When P has been calculated it should be multiplied bfactor of 0.85 to allow for turning, minor stoppages, eon straightforward sites: on irregular shaped sites thtime lost through these activities may be greater.

4.9 The rate of input of earthwork material to agiven area of fill should be assessed from the numbeloads per hour and the approximate capacity of theearthmoving machines. The rate of input in terms ofcompacted volume in m /hr must not exceed the3

potential output of the compactor or compaction team


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l 4.10 The depth of layer should be checked reguking using a probe in the loose material or by smallses excavations in the compacted material. The relaten between loose and compacted thickness will quickn at become apparent and probing of the loose layer c

precedence. The uniform coverage of the area to be

compaction plant should be ensured by generalnote supervision of the fill area.ting

4.11 It is also necessary to check regularly theed frequency of vibration of vibrating rollers ander vibrating-plate compactors, to ensure that it is as s

in the manufacturer's specification. The SHW, in S of Clause 612.10, requires vibrating rollers to be equon or provided with devices indicating the frequency fied. vibration of the mechanism which can easily be re

inspectors, together with the speed of travel. Vibrating plate compactors are not required to have devicest provided or be equipped, but the frequency of vibraand must still be measured to ensure that they are ope

at the frequency of vibration recommended by theed manufacturers. One way of achieving this is to us

vibrating wand frequency measuring device, held

continuously, systematically and efficiently, and the of input of material for compaction does not exceed thoutput of the compaction plant.

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compacted and the continuous operation of the

against an appropriate part of the machine.

4.12 In summary, it is necessary to ensure thecorrect layer thickness of deposited material, that thespreading and compaction machinery are operating

Over-compaction of materials

4.13 When the moisture content of a soil exceeds thoptimum moisture content for the compactive effortbeing applied, the compaction specified may produceover-compaction of some soils. Over-compaction iscompaction of the whole layer to a point of saturation,within the acceptability limits of the Specification. Over-compaction will manifest itself as remoulding ofthe surface of the compacted soil or severe permanentdeformation upon passage of the compactor. This is thresult of a reduction in air-voids to a low level with thegeneration of excess pore water pressures. Note thatelastic deformation (the `rubber mattress' effect) is notnecessarily indicative of over-compaction in the surfacelayer but indicates the generation of excess pore waterpressures in one or more of the underlying layers.


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Although these conditions will dissipate with time, thimay be long with cohesive soils. If remoulding of thesurface or severe permanent deformation develops wcohesive soils first check that the moisture content ofthe material is below the acceptable upper limit. If soconsider one or more of the following correctivemeasures:

(a) reduce the number of passes;

(b) increase the depth of compacted laye

(c) temporarily cease compaction;

(d) change the method of excavating andhauling the material, and size of plantused;

(e) dry the material by rotavation or thelike.

NOTE: The use of lighter compactionequipment with their own particular layerthicknesses and passes will not necessarilyimprove matters.

The measure applied should be related to the cause the condition of the material and the economicconsequences, and must be agreed by the Engineer

4.14 Before concluding that over-compaction istaking place, a few trial holes should be excavated tothe bottom of the layer to ensure that full compaction(near saturation conditions) occurs throughout the todepth of layer. If the bottom of the layer is not in asaturated condition then over compaction has not takplace and the compactive effort should be maintainedits original level in order to ensure the lower part of thlayer achieves the correct dry density. Over-compaction is not a serious problem with most soiltypes encountered. (With chalk, however, over-compaction can lead to problems of instability andassociated construction delays and a reduction incompactive effort is advisable.) When the compactiveffort is reduced it should be deemed to be a tempormeasure and the specified compactive effort should breverted to from day-to-day to check whether soilconditions still require the modified treatment. Ifacceptability of the material is controlled by MCV, thematerial at MCV less than about 10 may be prone toover-compaction when using Methods 1 and 2 of SH


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s Table 6/4. The earthworks design should take ovcompaction into account when setting acceptabili

ithlimits, for example by using these materials whicbe susceptible to over compaction in the core of

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Poorly compacted materials

4.15 Poor compaction of a material is difficult toidentify as the surface of the poorly compacted layerwill often appear to be well compacted. Unlike anover-compacted material which has a moisture contein excess of the optimum moisture content for theapplied compactive effort, poorly compacted materialare well dry of the optimum moisture content for theapplied compactive effort. Consequently, the poorlycompacted layer is also initially strong and does notdeform under traffic. However low densities will bepresent deeper in the layer and large voids can occurnear the bottom of a layer. In the longer term, thematerial will be able to take up any available watercausing the material to weaken with resulting settlemat the surface. The only way to check for voids is bydigging small trial holes and inspecting the condition the material in the lower part of the layer. In general,materials placed at MCV in excess of about 14 may bpoorly compacted when the method specification forcompaction of earthworks is applied strictly. In orderremedy the situation, the thickness of layer should bereduced; reducing the depth of layer will generallyproduce better results than increasing the number ofpasses.

4.16 Designers should be aware of the acceptabillimits which may lead to over-compaction or poorcompaction. In order to make maximum use ofmaterials the engineer should consider at the designphase of earthworks where and how these materials be used.

Testing within the method specification (duringmain works compaction)

4.17 For method specification applications,provision has been made in SHW Sub-Clause 612.9 the Engineer to carry out field density tests oncompacted materials. The tests should be made onlythe following circumstances.


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Chapter 4 Volume 4 Section 1Compaction of Earthworks Materials Using the Method Specification Part 5 HA 70/94

ed

(a) As a basis of settlement whencompliance with the specified compactionrequirements is in dispute.

(b) When it is suspected that despitecompliance with the Specification the state ofcompaction achieved is inadequate to ensurestability of the fill. If the tests indicateinadequate compaction a Variation Ordershould be issued to cover the necessaryremedial works.

(c) If alternative plant or techniques forcompaction are proposed which are notincluded in SHW Table 6/4.

4.18 The results of such trials using one Class ofmaterial stated in SHW Table 6/1 should not be applito the other Classes of material without further trialsbeing undertaken.


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Classify soilSHW Table 6/1 specifies Method number

Classify compactor -Type, Mass, Width/Area/No. of wheels

No. of passes, N, and depth of layer, Dfrom SHW Table 6/4

Potential output of compaction plant -

P = WVD x 0.85/N

where W = Effective width

V = Speed of travel

0.85 = Loss of efficiency (para 4.8)

Rate of earthmoving

A = loads per hour x

approx. volume per load

Is P > A?NO YES

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3.

Reduce rate of earthmoving

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Provide more compaction plant

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Stop work

Proceed, continue to -

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Ensure uniform coverage

Check thickness of layer

Check thickness and speed

of vibrating equipment

Recheckoutputs

Fig. 4.1 Flow Chart for the control of method specification for the compaction of earthworks

(after Parsons, 1992).



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Volume 4 Section 1 Chapter 5Part 5 HA 70/94 Compaction of Earthworks Materials Using the End-Product Specification

5. COMPACTION OF EARTHWORKSMATERIALS USING THE END-PRODUCTSPECIFICATION

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General

5.1 To apply the end-product specification, denstesting will be needed to ensure adequate compactioachieved, ie that the percentage dry density given inSHW Table 6/1 has been achieved or bettered. Appendix A explains how to calculate dry density. Tthickness of loose material prior to compaction islimited to 250mm (SHW Sub-Clause 608.1 (iii)) so theffective control can be maintained. In-situ bulkdensity and moisture content determinations arerequired to ascertain the in-situ dry density using theformula in Appendix A. In addition, laboratory testingis required to determine whether the dry densityachieved on site meets the percentage of the specifilaboratory compaction test given in SHW Table 6/1.

Classes of material are given in Table 6/1 of SHW amaterials which require an end-product specificationas follows:

(a) Class 2E reclaimed pulverized fuel acohesive materials as general fill. Compactiorequirement: 95% of maximum dry density oBS 1377:Part 4 (2.5kg rammer method);

(b) Class 6K and 6M materialssurrounding corrugated steel buried structure(The upper bedding, Class 6L, requires nocompaction). Compaction requirement: 90%of maximum dry density of BS 1377:Part 4(vibrating hammer method). Class 6M canhave other compaction requirements if statedAppendix 6/1;

(c) Classes 6N, and 6P fill to structures.Compaction requirement: 95% of maximumdry density of BS 1377:Part 4 (vibratinghammer method).

(d) Class 7A fill to structures. Compaction requirement: 100% of maximumdry density of BS 1377:Part 4 (2.5kg rammermethod) or a dry density corresponding to 5%air voids at the field moisture contentwhichever is the lower;



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(e) Class 7B fill to structures andreinforced earth. Compaction requirement: 95% of maximum dry density of BS 1377:Part4 (2.5kg rammer method);

(f) Class 9C cement stabilized pulverisedfuel ash cohesive material. Compactionrequirement: 95% of maximum dry density ofBS 1924:Part 2 (2.5kg rammer method);

Types of in-situ bulk density test (SHW Sub-Clause612.15)

5.2 The sand-replacement test is fully described inBS 1377: Part 9 (1990) and is the preferred method inthe UK for the determination of in-situ bulk density. Itis, however, laborious, time consuming and prone toerror in wet non-cohesive soils where slumping of theexcavated hole can occur and in dry and fissured soilsIt may be used on fine, medium and coarse grainedcompacted soils.

5.3 Nuclear methods for determining density andmoisture content are popular because of their speed omeasurement and the greater reliability of currentlyavailable instruments compared with the earlier modeThey may be used when required in SHW Appendix 6or when permitted by the Engineer and as an adjunct sand replacement testing (see Appendix D). Where thtwo methods are to be used, they should be used in thearly stages of the Contract to calibrate nuclear methoon site for each class of material (see Paragraph D3).

Tests in Pulverised Fuel Ash (PFA)

5.4 After PFA has been compacted, loose materiacan be present on the surface of the layer, even thougthe rest of the layer below meets the end-productspecification. This loose material will, however,become compacted when the next layer above is placand compacted. Field density measurements will berequired to ensure compaction has met the end-produspecification. Any loose material on the surface of thelayer at the testing location should be removed beforetesting as this will become compacted by the next laye



Chapter 5 Volume 4 Section 1Compaction of Earthworks Materials Using the End-Product Specification Part 5 HA 70/94

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The depth tested below the removed material should bsufficient to include the previously loose material on thsurface of the underlying layer. Usually the depth ofoverstressed material is about 100mm but depends onthe nature of the PFA and the size and type ofcompaction plant. Due to the variability of PFA and theffect this can have on compaction, SHW Sub-Clause601.17 enables the Engineer to keep a record of thesources, and places the onus on the Contractor toprovide the requisite data including moisture content odelivery, and the optimum moisture content andmaximum dry density of each consignment. For PFA igeneral fill applications, Class 2E, the end-productspecification relies on achieving 95% maximumlaboratory dry density. If the weight of theembankment is critical to the design, then the bulkdensity of the PFA must fall within the limits given inthe design. The bulk density limits are based onconsideration of the settlement of the soil beneath theembankment expected in the design, while the purposof the dry density requirement is to achieve adequatecompaction within the fill.



Volume 4 Section 1 Chapter 6Part 5 HA 70/94 Landscape Areas



6. LANDSCAPE AREAS

On-site landscape areas

6.1. On-site landscape areas can be excellentlocations for use as temporary holding areas foracceptable fill where there is the possibility that theContractor may need more fill in a particular area, orfor placing surplus material without needing to findadditional off-site tips.

6.2 The reduced compaction requirement inlandscape areas means that materials with wideracceptability criteria may be used thus leaving the betterengineering materials for fill areas.

6.3 Areas of special interest, eg trees, requireprotective fencing and careful monitoring. These areasshould be treated in a similar way to areas ofearthworks instrumentation which also need to becarefully protected.

6.4 Any special requirements for topsoil should becarefully monitored and controlled where necessary.

6.5 All on-site landscape areas should be subjectedto the Geotechnical Certification process. Otherlandscape operations, such as to strip topsoil, or otherearthwork operations to produce ecologically differentconditions should also be subject to GeotechnicalCertification. Procedure for Geotechnical Certificationis covered in HD22 (DMRB 4.1.2).

Volume 4 Section 1 Chapter 7Part 5 HA 70/94 Information on Some Specific Materials

7. INFORMATION ON SOME SPECIFICMATERIALS

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ilvel

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es

General

7.1 Some general information is given below onsome specific materials which complements theinformation in HA 44 (DMRB 4.1.1). HA 44 (DMRB4.1.1) covers a wider range of materials in more detaand should be consulted if more information is requir

Chalk

7.2 Chalk is sensitive to disturbance at excavatioduring transportation, placing and compaction andshould be handled with care. HA 44 (DMRB 4.1.1)includes information on classification of chalk and theappropriate method of compaction.

7.3 If small pockets of soft chalk are encountereduring construction in hard chalk areas, it may be beto leave the compaction method, as required for theharder chalk, unchanged and either remove occasionunstable material as it is found or alternatively allowdelays for the softer material to recover stability. Reducing the compactive effort to suit the soft chalkwill risk long-term settlement in the under-compactedhard chalk.

7.4 If it is found that the compaction requirementconsistently causes instability on site, the Engineer mreduce this requirement.

Minestone

7.5 Minestone is the generic name for unburntcolliery shale which consists mainly of shales,mudstone and siltstones. Minestone is extremelyvariable and the properties of material coming from atip may change significantly as excavation progresseThere should therefore be frequent sampling and tesat the source.

7.6 The argillaceous materials in Minestone aremoisture susceptible and are likely to soften and swewhen weathered. Large amounts of weathering occuolder tips as they tend not to have been compactedwhen tipped and have been exposed to the elementslonger. On the other hand, newer tips will contain

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al

ay

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llr in

amounts of unweathered pyrites. It will therefore benecessary to consider the properties of the minestoand the use to which it is to be put. Older weatherematerial, timber (pit props etc) and large lumps shonot be used.

7.7 Minestone can be chemically reactive and iimportant that as much emphasis is placed on chemtests as is placed on physical ones. There arelimitations on its use in the vicinity of concretestructures as a permitted constituent in Table 6/1. 7.8 One source of information is British CoalProperty, Unit 21, Philadelphia Business Park,Houghton-le-Spring, Tyne and Wear DH4 4TG.

Pulverised Fuel Ash (PFA)

7.9 Details on the properties of PFA are given iHA 44 (DMRB 4.1.1). Slopes of PFA are particularlsusceptible to erosion if not protected. Care shouldtaken to ensure that the PFA is covered as soon aspossible after forming the slope and that the topsoilused remains stable. It is the Contractor's responsito ensure that the site is adequately drained duringconstruction.

7.10 Further information on the use of PFA can bfound in Dhir and Jones (1992). 7.11 PFA and Minestone are industrial by-produand their use has environmental benefits. The beneinclude the reduction in the size and number of spotips and the saving of natural resources such as grabeds. By conserving natural resources, the amoundisturbance of green field sites is reduced and theproductive life of resources is extended.

Geotextiles

7.12 SHW Clause 609 and HA 44 (DMRB 4.1.1)provide details on the use and handling of geotextilduring construction.

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7.13 It is important that geotextiles do not sufferphysical or chemical damage during construction as thcan lead to a reduced life and the risk of instability. SHW Clause 609 specifies the requirements to prevendamage and hence ensure that the design liferequirements are met. Damage can be caused bymechanical effects, such as:

(a) puncturing by sharp projections;

(b) tearing during placement or byconstruction plant running over the geotextile once laid

The main cause of chemical damage is the embrittlingeffect that ultra-violet light has on the geotextile. Theinclusion of Carbon within the polymers used to makethe geotextiles reduces this effect.



Volume 4 Section 1 Chapter 8Part 5 HA 70/94 Effects of Construction Plant Operations

8. EFFECTS OF CONSTRUCTION PLANTOPERATIONS

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hat

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General

8.1 At higher moisture contents the range of typeof plant which can be used will be restricted. Howevthis should not inhibit the use of wetter cohesivematerials. Providing the site investigation is adequatand gives information on the moisture conditions of sin-situ then it is the Contractor's responsibility to seleand use plant which can operate effectively in theparticular conditions and not to assume that the largeavailable machines can be used. The Contractor haresponsibility under SHW Sub-Clause 602.1 to mainthe acceptability of materials and so plant which willreduce the strength of material either remaining in-sibeing transported and placed or in its final compactestate should not be used.

Minimizing the effects of construction plantoperations

8.2 SHW Sub-Clauses 617.1 and 617.2 require tsub-formation and formation be protected fromconstruction plant not involved in the construction ofcapping and sub-base. If necessary protection shouin addition to any weather protection already provideAlso in SHW Sub-Clause 617.3, the sub-formation aformation must be protected from construction plant they are within 300mm of existing ground level, aftertopsoil has been stripped.

8.3 During lime stabilization processes wherepowdered lime is being used, lime spreading androtavation plant should be operated in such a manneas to keep the amount of lime dust to a minimum. Thamount of lime dust in the air can be reduced byensuring the lime discharging outlet of the spreadingplant and the hood of the rotovating plant are efficiencurtained. Although this will prevent most dust fromescaping, consideration may need to be given to thesurrounding areas outside the highway boundary toensure there is no hazard to health or property. TheLime Stabilization Manual (1990) contains informatioon safety aspects.

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ser,

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8.4 When working in urban areas it is importantthat the Resident Engineer is alert to the problemswhich could arise when earthmoving construction planand vibratory compaction plant are operating. It isimportant that any restrictions on working hours, noiselevels and vibration levels specified in the Contract arestrictly adhered to in order to keep noise, vibration andvisual impact to a minimum. New (1986) providesguidelines on acceptable vibration levels and BS 7385provides guidance on the Evaluation and Measuremenfor vibration in buildings.

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Volume 4 Section 1 Chapter 9Part 5 HA 70/94 Preventing the Spread of Plant and Animal Diseases



9. PREVENTING THE SPREAD OF PLANT ANDANIMAL DISEASES

9.1 The Engineer should make contact with theMinistry of Agriculture, Fisheries and Food DivisionalVeterinary Officer (DVO) and, in England and Wales,the Senior Plant Health and Seeds Inspector (SPHSI); orin Scotland, the Principal Agricultural Officer (PAO)for the area concerned; or in Northern Ireland, theDepartment of Agriculture, Animal Health Division orAgricultural and Food Science Division, to enquire if:

(a) any statutory restrictions currentlyapply to the site or in the immediate locality, and ifthere is any need for special precautions to be taken;

(b) they know of the presence of anysoil-borne diseases in or near where the Contractor willbe working.

The Engineer should be aware of these requirementsand have made comment in the `Special Requirements'or within SHW Appendix 6/2.

9.2 If the site involves removing trees, then it isrecommended that the Engineer consults the ForestryCommission Plant Health Inspector for the area foradvice on how to avoid spreading tree diseases. InNorthern Ireland, consultation should be with theForestry Services Officer of the Department ofAgriculture.

9.3 Further advice on precautions to be taken isgiven in Ministry of Agriculture, Fisheries and Foodpublication "Preventing the Spread of Plant and AnimalDiseases - A Practical Guide" (1991).

Volume 4 Section 1 Chapter 10Part 5 HA 70/94 Instrumentation and Monitoring



10. INSTRUMENTATION AND MONITORING

10.1 The installation of instrumentation isspecifically included in a Contract for collectinginformation important to the successful completion anddesign life of the construction. The construction andlonger term performance of the Works will depend onthe information recorded.

10.2 The instrumentation should be installed,monitored and maintained as conscientiously as anyother aspect of the Works.

10.3 It may be necessary to control site operations inorder to avoid damage to the instruments, to analyze theresults obtained and to have a defined set of criteria tocompare the observed results against. Investigatory andaction levels should be known.

Volume 4 Section 1 Chapter 11Part 5 HA 70/94 Feedback



11. FEEDBACK

11.1 This is an important aspect of construction. Whether the Works have been a success or a problem,will add useful information for future designs andconstruction techniques.

11.2 Under Geotechnical Certification procedureHD22 (DMRB 4.1.2), the Engineer's Representative isrequired to produce a Geotechnical Feedback reportdetailing the location and nature of materialsencountered, particularly geotechnical problems andtheir solutions. The format of the GeotechnicalFeedback report is given in Appendix H of HD22.

Volume 4 Section 1 Chapter 12Part 5 HA 70/94 References

12. REFERENCES

o

s

1. Design Manual for Roads and Bridges(DMRB).

HA 43 - Geotechnical considerations andtechniques for widening highway earthworks(DMRB 4.1.2).

HA 44 - Earthworks: design and preparation contract documents (DMRB 4.1.1).

HA 48 - Earthworks: maintenance of highwayearthworks and drainage (DMRB 4.1.2).

HD 22 - Ground Investigation and EarthworkProcedure for Geotechnical Certification(DMRB 4.1.2).

2. Manual of Contract Documents for HighwayWorks (MCHW).

Volume 0: Model contract document for majoworks and implementation requirements:

SD5 - Model contract document forHighway Works (MCHW 0.1.1)

SA 3 - Testing in HighwayConstruction Contracts (MCHW 0.3.3

Volume 1: Specification for highway works(December 1991): HMSO (MCHW 1).

Volume 2: Notes for guidance on thespecification for highway works (December1991): HMSO (MCHW 2).

Volume 4: Bills of quantities for highwayworks (December 1991): HMSO (MCHW 4).

Section 1: Method of Measurement forHighway Works.



3. British Standards Institution

f

:

r

)

BS 5607 Code of practice for safe use ofexplosives in the construction industry. BSILondon.

BS 1377 Methods of test for soils for civilengineering purposes. BSI London.

BS 1924 Stabilized materials for civilengineering purposes. BSI London.

BS 7385 Evaluation and measurement forvibration in buildings.

4. BRITISH LIME ASSOCIATION (1990). Lime stabilization manual. 2nd Edition.

5. DHIR R K and JONES M R (1992). The useof PFA in construction. Proceedings of thenational seminar held at the University ofDundee on 25-27 February 1992.

6. HOEK E and BRAY J W (1981). Rock slopeengineering. 3rd Edition Institution of Miningand Metallurgy.

7. HUDSON J A (1989). Rock mechanicsprinciples in engineering practice. CIRIA.

8. JOHNSON P E (1985). Maintenance andrepair of highway embankments: studies ofseven methods of treatment. Department ofTransport, TRRL Research Report RR 30,Transport and Road Research Laboratory,Crowthorne.

9. MATHESON G D (1983). Rock stabilityassessment in preliminary site investigations -graphical methods. Department of Transport,TRRL Laboratory Report 1039, Transport andRoad Research Laboratory, Crowthorne.

10. MINISTRY OF AGRICULTURE, FISHERIESAND FOOD (1991). Preventing the spread ofplant and animal diseases: a practical guide. MAFF Publications, London SE99 7TP.



Chapter 12 Volume 4 Section 1References Part 5 HA 70/94

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11. NEW B (1986). Ground vibrations caused bycivil engineering works. Department ofTransport, TRRL Research Report RR 53,Transport and Road Research Laboratory,Crowthorne.

12. PARSONS A W (1992). Compaction of soilsand granular materials: a review of researchperformed at the Transport ResearchLaboratory. HMSO.

13. PERRY J (1989). A survey of slope conditionon motorway earthworks in England andWales. Department of Transport, TRRLResearch Report RR 199, Transport and RoaResearch Laboratory, Crowthorne.



Volume 4 Section 1 Chapter 13Part 5 HA 70/94 Enquiries



13. ENQUIRIES

All technical enquiries or comments on this Standard should be sent in writing as appropriate to:

Head of Road Engineering and Environmental DivisionThe Highways AgencySt Christopher House N S ORGAN Southwark Street Head of Road Engineering andLondon SE1 0TE Environmental Division

The Deputy Chief EngineerRoads DirectorateThe Scottish Office Industry DepartmentNew St Andrews House J INNESEdinburgh EH1 3TG Deputy Chief Engineer

Heads of Roads Engineering (Construction) DivisionWelsh OfficeY Swyddfa GymreigGovernment BuildingsTy Glas Road B H HAWKERLlanishen Head of Roads EngineeringCardiff (Construction) Division

Assistant Chief Engineer (Works)Department of the Environment forNorthern IrelandRoads Service HeadquartersClarence Court10-18 Adelaide Street W J O'HAGANBelfast BT2 8GB Assistant Chief Engineer - (Works)

Dd '100D

100%w

Va ' 1&Dd

Dw

Dw

Ds

%w

100100(%)

Volume 4 Section 1Part 5 HA 70/94 Appendix A


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A. CALCULATION OF DRY DENSITY AND AIRVOIDS

A.1 Dry density (D ) is the mass of the dry soild

contained in unit volume of undried material:

where D = bulk density; the mass ofmaterial (including solidparticles and any containedwater) per unit volumeincluding voids.

w = moisture content; themass of water whichcan be removed fromthe soil, usually byheating at 105 C,o

expressed as apercentage of the drymass.

A.2 Air voids (V ) is the volume of air voids in thea

soil expressed as a percentage of the total volume of thesoil and is usually calculated by:

where D = the dry density of the soild

(Mg/m )3

D = the density of water (Mg/m )w3

(1.0 Mg/m is normally used,3

which is the density at 20 C)o

D = particle density (Mg/m )s3

w = moisture content; the mass ofwater which can be removedfrom the soil, usually byheating at 105 C, expressed aso

a percentage of the dry mass.

Volume 4 Section 1Part 5 HA 70/94 Appendix B

B. TESTING WITHIN THE SHW METHODSPECIFICATION (DURING MAIN WORKSCOMPACTION)

gificant

rea.

sults a

ale

fansanith

ee,

mean air voids' jVa

n

standard deviation(sd) 'j V2

a &

[j Va]2

nn & 1

of air voids

B.1 To compare the difference in the state ofcompaction of suspect and approved areas, tests shobe carried out on areas in which materials are of thesame classification, having similar characteristics andwithin the Specification requirements for acceptabilityIt is for the Engineer to demonstrate that theContractor's compaction is inadequate beyondreasonable doubt. When measurements of the state compaction of an area are carried out, due allowanceshould be made for the variability of the test results, athe appropriate number of tests within an area shouldrelated to the accuracy required and the standarddeviation of the results obtained. It is recommendedthat initially a minimum of five tests be carried out ineach area. Air void measurements are used to minimthe effects of variations of materials. From these resuthe mean and standard deviation of the air voids foreach area can be calculated from;

where V = air voids (as defined in Appendix A)a

n = number of samples

Subsequently an additional number of tests may becarried out sufficient for the accuracy required usingTable 1 with the standard deviation obtained for thatarea. Usually the values of standard deviation liebetween +3% and +5% air voids. Having conductedsufficient testing, the Engineer should require remedimeasures to be taken in a suspect area only when thstate of compaction is shown to be lower than that of

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the approved area with which comparison is beinuld made, by a difference which is statistically sign

(with a 90% probability).

. B.2 To illustrate this approach, consider thefollowing results for an approved and a suspect a

of Approved Area -

nd sd of first five readings = +3.5%. Using Table 1 for an be accuracy of mean air voids of +2%, a further 5 tests,

giving a total of 10, were conducted. The 10 refrom these tests gave a mean air voids of 5.0%,

similar standard deviation and hence a confidenceise interval of 3%-7%. lts

Suspect Area -

sd of first five readings = +3.0%. Using Table 1 for an

would lead to further testing.

accuracy of mean air voids of +2%, a further 3 tests,giving a total of 8, were conducted. The 8 results fromthese tests gave a mean air voids of 5.5%, a similarstandard deviation and hence a confidence interval o3.5% - 7.5%.It can be seen that the ranges of the mein the suspect and approved areas overlap and so it cbe concluded that there is no significant difference, wa 90% probability, between the mean air voids in bothareas, and that the suspect area achieves adequatecompaction.

B.3 If the standard deviation had changed with thaddition of further tests then a new accuracy would bobtained from Table 1 which, if it were not acceptable

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Volume 4 Section 1Appendix B Part 5 HA 70/94


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TABLE 1

Numbers of tests required to produce results having mean values of air voids within various limits of error with aprobability of 90%

Value of standard Number of tests for limit of error of:

deviation of air voids %

+1% air +2% air +3% air +4% air +5% airvoids voids voids voids voids

+1 5 3 3 3 2

+1.5 8 4 3 3 3

+2 13 5 4 3 3

+2.5 19 7 4 4 3

+3 26 8 5 4 4

+3.5 35 10 6 5 4

+4 45 13 7 5 4

+4.5 57 16 8 6 5

+5 70 19 10 7 5

+5.5 84 23 11 8 6

+6 99 27 13 8 6

+6.5 116 31 15 9 7

+7 135 35 17 11 8

Volume 4 Section 1Part 5 HA 70/94 Appendix C

C. TRIALS TO ENSURE THAT PROPOSED NEWMETHODS ACHIEVE ADEQUATECOMPACTION

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dn

. to

C.1 SHW Sub-Clause 612.6 has been included tofacilitate the development of new plant or techniquesfor soil compaction. Where the Contractor proposes touse a type of plant or method other than those given inSHW Table 6/4, it is recommended that the provingtrials be carried out in the following manner.

(a) The trial area should be located onmaterial compacted in accordance with SHWClause 612 to a depth of at least 1 metre. Thematerials in the trial area must have the sameclassification, similar characteristics and bewithin the Specification requirements foracceptability as those on site. The length of thetrial area should be about 15 to 20 metres andthe width at least four times the overall widthof the largest item of plant to be used.

(b) The trial area should be divided intotwo equal widths and acceptable materials, asdefined in SHW Clause 601 and the Classes inSHW Table 6/1 upon which the Contractorintends to use the proposed alternative plant ormethod, deposited evenly over each half. Thedepth of the material in the first half should besuch as will produce the appropriate depth ofcompacted layer as required in SHW Table 6/4for the approved plant to be used in the trial,and in the second half, the depth proposed bythe Contractor for the alternative plant ormethod. Care should be taken to ensure thatuniform soil conditions are achieved over thewhole trial area.

(c) The trial area should then becompacted; the first half by using the approvedplant according to the requirements of SHWTable 6/4 and the second half according to theContractor's proposals.

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(d) After compaction, determinations othe state of compaction, in accordance withsand-replacement method or by nuclear gamethods as described in BS 1377: Part 9

(1990) should be made in each half of thecompacted area. For each half the air voids

depth of the compacted layer, except where surface material has been loosened, in whiccase the loose material should be removedto testing. Sufficient tests should be carried

in each half of the compacted area to yieldresults on which decisions can be made on a

sound statistical basis. That is, the numbertests in each half of the compacted area sh

be progressively increased until, by satisfactoanalysis, it is shown that any difference

statistically significant (with a 90% probability(see Table 1) or until the limits of error of eamean has been reduced to +1% of air voids (see

Table 1). In order to show there is a significadifference between the means, the confidenranges, as deduced in a similar way to the

example given in Appendix B, should notoverlap.

(e) Having conducted sufficient tests aneither shown a significant difference betwee

the means or shown a high degree ofconfidence in the value of each mean, the

Contractor's proposed method should beapproved if the mean of its air void

air voids obtained from the approved methodThis is a more rigorous approach comparedthat in Appendix B as the new approvedmethod is likely to be used throughout the

earthwork's construction.

obtained should be the average for the total

between the mean air voids of the two halves is

determinations is less than or equal to the mean

(f) If the Contractor cannot achieveadequate compaction using an initial suggestedmethod, then increasing the compactive effortmay be considered.

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Volume 4 Section 1Part 5 HA 70/94 Appendix D

D. NUCLEAR METHODS

ation

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, the

ects

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r

D.1 Nuclear methods are suitable for use on fine,medium and coarse grained compacted soils. SHWSub-Clause 612.15 states that the nuclear gauges usshall be calibrated in accordance with BS 1377: Partand their use shall comply with the safety requiremenof SHW Clause 123. Nuclear gauges operate in twodifferent modes for the determination of bulk density.

(a) The direct transmission method is therecommended method for measuring bulkdensity. It involves inserting a probecontaining a source of gamma radiation downpreformed hole in the soil and placing a gammdetector at the surface of the soil. Thistechnique measures the amount of attenuatioof the gamma particles reaching the detectorwhich is a function of the average bulk densitover the depth to which the source is inserted

(b) The backscatter method uses both agamma source and detector at the surface ofsoil, and as a consequence tests only a thinupper layer of soil. This method should onlybe used for bulk density determinations whenthe probe of the direct transmission methodcannot be inserted into the soil.

The determination of moisture density relies on thereduction in the speed of neutrons, from a fast neutrosource, as they collide with hydrogen nuclei in the soThe source and detector are placed on the surface ofsoil but the technique can be used with either directtransmission or backscatter modes when determiningbulk density. The dry density of the soil is thedifference between the bulk density and the moisturedensity, and the moisture content is calculated by thepercentage of moisture density to dry density. Thesevalues are usually calculated by a micro-processor onthe gauge. It is essential that the calibrations prepareby the manufacturers of the instruments are checkedeach soil type and, when using the backscatter methoafter any significant change in method of compactionIn checking calibrations, it is important to comparevalues of bulk density and moisture density for thegamma radiation and neutron radiation techniquesrespectively (see Paragraph D4). For the backscattemethod, it is recommended that the nuclear gauge be



calibrated insitu.

D.2 The principal sources of variation in calibrand in measurement are:

ed 9, (a) the effects of the chemical constitts of the soil on:

(i) the absorption of gamma

furnace slag) which affects thecalibration for the measurement of

bulk density; aa (ii) the presence of hydrogen

which is not removed during then drying process; for example soils

containing organic matter, or miney such as gypsum, with high amount. chemically bound water which can

nuclear gauge. Some elements su the cadmium, boron and chlorine can

have an effect on moisture densitmeasurements.

(b) for the direct transmission methodeffects of variations in particle size on the

probe;nil. (c) for the backscatter method the eff the of density gradients within the layer; the

density of the near surface material sampthe gauge bears little or no relation to the

overall average density of the layer;

(d) for both measurements of bulk deand moisture density, heterogeneity withilayer can lead to unrepresentative results

d for (e) lack of contact between the gaugd, soil surface can affect results for all mod

. operation.

radiation (for example by iron in blast

be distinguished from free water by the

degree of disturbance created by inserting the


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Volume 4 Section 1Appendix D Part 5 HA 70/94

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e

D.3 Ideally the calibration of nuclear gauges shouldbe checked by performing both sand replacement andnuclear testing in the early stages of a scheme. Asconfidence increases in the relation between the nuclearesults and sand replacement results on a particular sitethe intensity of sand replacement testing may bereduced.

D.4 The basic calibrations for a nuclear gauge arein terms of relations between intensity of detectedgamma radiation at the detector and bulk density, andbetween neutron intensity at the detector, which isrelated to the rate of arrival of the slow neutrons, andmoisture density. It is important that the correctparameters are compared and subjected to correction, ibulk density (nuclear) with bulk density (sandreplacement), and moisture density (nuclear) withmoisture density (sand replacement and oven drying). Note that moisture density = bulk density - dry density. Typical results under controlled conditions are givenbelow, for a well graded sand, illustrating how suchcomparisons would allow subsequent corrections to beapplied to the nuclear gauge readings for that soil.

D = 1.297 D - 0.532SR NG

M = 0.856 M + 0.026SR NG

where D = bulk density by sandSR

replacement (Mg/m )3

D = bulk density by nuclear gaugeNG

(Mg/m )3

M = moisture density by sandSR

replacement (Mg/m )3

M = moisture density by nuclearNG

gauge (Mg/m )3


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