Concept: While excavating the soil from the borrow pit and after that compacting it, the mass of solids and its specific gravity will not change, and hence, the volume of solids remains constant even after compaction. The Total volume(V) of soil is given by V=Vv+Vs Where V= Total volume of soil, VV= Volume of voids, Vs= Volume of solids Divide the equation (i) by Vs (Volume of solids)
V
Vs
=
Vv
Vs
+
Vs
Vs
V
Vz
=
Vv
Vs
+1
V
Vs
=e+1 VS=
V
(1+e)
Calculation: Condition - I: Filling ef=0.7 and Vf=8,50,000m3 So, Volume of solids in filling (Vsf) Vsf=
Vf
(1+ef)
=
850000
(1+0.7)
=500000m3 Condition-I: Excavation The volume of solids will be the same as that of during fill i.e. Vsf=500000m3 eexc=0.8 So, find the volume of excavated soil (Vexc) Vs(exc)=
Vexc
(1+eexc)
500000=
Vexc
(1+0.8)
Vexc=500000×(1+0.8)=900000m3 The estimated cost for the filling work is (in Rs.) = 10 × 900000 = 90,00,000