Question

A water harvesting pond is to be constructed by constructing an embankment across a narrow valley.

The top width of the embankment is kept at 3.6 m. using the information in the Table Q8, and taking the upstream and downstream side slopes as 3:1 and 2:1 respectively, a settlement allowance of 12.5%:

1. .       Fill up the table and estimate the earth volume required to construct the dam. Show sample calculations only.
2. .     Sketch the plan view, longitudinal section and centre cross section of the dam.

Table Q8

Station (m)	Ground elev. (m)	Fill height (m)	Distance (m)	End areas (m2)	Volume (m3)
0+50	35.0	0
+68	32.7	2.3
1+00	25.9	9.1
+37	21.5	13.5
+53	20.0	15.0
+75	19.8	15.2
2+00	19.5	15.5
+19	20.3	14.7
+32	20.3	14.7
+36	18.8	16.2
+40	18.2	16.8
+43	18.5	16.5
+46	19.6	15.4
+59	19.8	15.2
3+00	20.8	14.2
+35	27.7	7.3
+60	31.6	3.4
3+96	35.0	0

Answer 1

End area = {(3.6+3.6+2d+3d)÷2 }×d

Here, d = fill height

Volume = {(end area 1 + end area 2 )÷2}× distance

here, settlement allowance means we have to increase the fill height by 12.5% which will fill the requirements even if there a settlement.