DHARMCOMPACTION OF SOIL 441If the volume of the soil to be excavated from the borrow pit is Vb,then:
V
Ve
eb
ib
i=+
+1
1 =(.)
(.)1090
1 0 406+
+∴ Vb =190
1 40620 000.
.× , m^3 = 27.027 m^3The cost of compensation to be paid to the owner of the borrow area = Rs. (1.50 × 27,027)
= Rs. 40,540.
Example 12.4: A soil in the borrow pit is at a dry density of 17 kN/m^3 with a moisture content
of 10%. The soil is excavated from this pit and compacted in a embankment to a dry density of
18 kN/m^3 with a moisture content of 15%. Compute the quantity of soil to be excavated from
the borrow pit and the amount of water to be added for 100 m^3 of compacted soil in the em-
bankment. (S.V.U.—B.E. (Part-time)—Apr., 1982)
Volume of compacted soil = 100 m^3
Dry density of compacted soil = 18 kN/m^3
Weight of compacted dry soil = 100 × 18 = 1800 kN
This is the weight of dry soil to be excavated from the borrow pit.
Weight of wet soil to be excavated = 1800 (1 + w) = 1800 (1 + 0.10) = 1980 kN.
Wet density of soil in the borrow pit = 17 (1 + 0.10) = 18.7 kN/m^3
Volume of wet soil to be excavated =1980
18 7. = 105.9 m3Moisture present in the wet soil, in the borrow pit for every 100 m^3 of compacted soil =
1800 × 0.10 = 180 kN
Moisture present in the compacted soil of 100 m^3
= 1800 × 0.15 = 270 kN
Weight of water to be added for 100 m^3 of compacted soil
= (270 – 180) kN = 90 kN=90
981.m^3 = 9.18 klExample 12.5: The following data have been obtained in a standard laboratory Proctor
compaction test on glacial till:
Water content % 5.02 8.81 11.25 13.05 14.40 19.25Weight of container and 35.80 37.30 39.32 40.00 40.07 39.07
compacted soil (N)The specific gravity of the soil particles is 2.77. The container is 9.44 cm^3 in volume and
its weight is 19.78 N. Plot the compaction curve and determine the optimum moisture content.
Also compute the void ratio and degree of saturation at optimum condition.
(S.V.U.—B.E., (R.R.)—Nov., 1973)
The dry density values are computed and shown in Table 12.2.