Excavation work

Excavation Work

Reactor BuildingExcavation Work

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. Your company has been awarded to carry out the excavation work for the proposedReactor building (RB) near the sea shore. The area is covered with vegetation and thesuitable dewatering system shall be provided by others as per the requirement. A briefdescription of RB is given below.RB is a rectangular building conglomerate (Oriented NS) and measuring 80m along EWby 100m along NS in plan at FGL (Finished Ground Level). RB Comprises of a BG-1situated centrally, flanked between BG-2 ( on North side ) and BG-3 ( on South side) aswell as BG -4 (on East side ) and BG-5 (on West side). Remaining three utilitybuildings BG-6 (Northeast corner), BG-7 (Southeast Corner), BG-8 (Southwest Corner)and BG-9 (Northwest corner) are situated along the diagonals of the BG-1All the buildings are founded on the common base raft with top of raft at two differentlevels of 2m difference BG-1, 2 &3 at lower level and other buildings & BG-4,5,6,7,8 &9at higher level.The mile stone for starting the raft work by other contractor shall be 120 days from yourstart date. The dumping yard is 1000m from the site. The necessary road work forreaching the dumping yard shall be in your scope. Kindly, plan for the equipmentrequirement to complete the excavation work and handover the site for raft construction.Prepare a complete methods and equipment statement for the job.

copyright@Amit kumar2

Site demarcation


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Top view of buildings after completion of whole work926514837

ENcopyright@Amit kumar4

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Sectional elevation of site

Fig. Earth pressure diagramDry sand Density=1542kg/cumWet sandDensity:1600kg/cumCohesive soilCoefficient of cohesion C=60KN/sq.mcopyright@Amit kumar5

Assumed schedule of work


AssumptionsOperator is of average skill with operation factor of 0.80.Visibility is goodFactor of machine transmission is fairRolling resistance is 100lb/tonVegetation is present in the form of trees and bushes at sea shore with light densityTrees assumed are:

Hard woods is less than 25%


Water table is at 4.5m below ground level(G.L)Soil type is changing below water table and dredge level of 13mUpto water table sand is dry hving bank unit wt = 1542 kg/cumBelow W.T soil is wet sandy having unit wt.1600 b kg/cumBelow dredge level of 13m soil is cohesive having coefficient of cohesion 60 kN/sq.mPercent swell for dry sand = 15%For wet sand = 15%


ReconnaissanceSURVEYING Setting the R.L Marking the bounderiesFENCING THE BOUNDERIES Placing cones etc.PLACING THE SIGNBOARDSARRANGEMENTS FOR NIGHT LIGHTINGS


TIME REQUIRED SURVEYING - 2 DAYSFENCING - 1 DAYSIGNBOARDS AND NIGHT LIGHTINGS - 1 DAYPROCURE EQUIPMENT 1 DAY


Site cleaningCrawler dozers equipped with special clearing blades are excellent machines for land clearingClearing land operations:Removing all vegetation above the groundPiling-up the removed materials in windrows directionSelling the vegetation and removed treesRequired productivity= area/time = (14000 +8000)/8*3= 917sq.m /hr


Outside to center cleaning methodcopyright@Amit kumar12

Equipment selectionProduction factor for felling trees(power shift dozer):Table 1


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Considering 165 hp Dozer



Calculation sheet for land cleaningTaking 165 hp dozer (Medium dozer) CAT D6RTree count method:Time(in min) per acre for cutting=H(AB+M1N1+M2N2+M3N3+M4N4+DF)Where,A=effect of Tree density per acre(-30.254*(1.33+.5)+141.264*4+26.487*5.5+45.525(8.5+ 2.407/3) D(4*60-219.43)(8.5+ d/2)=0 =>1078.844-175.78D-10.34D2=0 => D=4.789 mProvide 30% extra for safety, D=1.3*4.789=6.226mTotal length of sheet pile at a point=13+6.226=19.226mProvide depth of embedment 20m with steel sheet pile.copyright@Amit kumar29

Contd.. Required sheet piles = = 166+133+166+110+250+250 = 1075 sheet piles

Estimated duration =20 days = 1075/20 = 53 piles /day copyright@Amit kumar30

Maximum capacity available is 20 piles /day for 20 m depthTaking two vibratory pile driver = 40 piles /day No. of days= 1075/40 = 26 days 6 day more than the allocated time period. copyright@Amit kumar31

Specification of pile driver

LRB 155copyright@Amit kumar32

ExcavationTime allocated to excavation work=65 days(excluding holidays)Required productivity of excavator=volume to be excavated/no.of hours allocated=(volume of excavated earth from site + volume of excavated earth for haul road preparation)in cum/time in hrs=(109440 + 13650)/(65*8)=236.712b cum/hr =236.712bcum/hr0.76bcum/blcy =311.463blcy/hr


Available excavators: Back hoe, Front shovelWe have to do excavation below ground level so we have selected backhoe for our excavation purpose.Method of excavation used is excavating earth and moving backward.



Selecting 2.5cy bucket size, Productivity=277.78bcy/hr

Date post:	11-Apr-2017
Category:	Engineering
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Excavation work

Engineering