An
irrigation distributory of the following dimensions is to be provided from ch.
0 to ch. 1000 downward. Ground has longitudinal slope 1 in 500 downward. GL. At
ch. 0 is 400.00 and CBL is 398.00. Calculate the levels at 100 m intervals,
record them in the table and calculate the earth work for distributory.
Solution:
Calculation
of earthwork
B = 2, S = 1
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Chainage
m
|
Height or Depth Differ
GL & CBL
|
Mean height or depth
d/m
|
Central area
B x d
M2
|
Area of sides
Sd2
M2
|
Total Sectional area
Bd + Sd2
M2
|
Distance between two stationsL
M
|
Quantity of earth work
Bd + Sd2
Cu.m.
|
0
|
2.00
|
-
|
-
|
-
|
-
|
-
|
-
|
100
|
1.90
|
1.95
|
3.90
|
3.802
|
7.702
|
100
|
770.2
|
200
|
1.80
|
1.85
|
3.70
|
3.423
|
7.123
|
100
|
712.3
|
300
|
1.70
|
1.75
|
3.50
|
3.062
|
6.562
|
100
|
656.2
|
400
|
1.60
|
1.65
|
3.30
|
2.723
|
6.023
|
100
|
602.3
|
500
|
1.50
|
1,55
|
3.10
|
2.402
|
5.502
|
100
|
550.2
|
600
|
1.40
|
1.45
|
2.90
|
2.107
|
5.007
|
100
|
500.7
|
700
|
1.30
|
1.35
|
2.70
|
1.823
|
4.523
|
100
|
452.3
|
800
|
1.20
|
1.25
|
2.50
|
1.563
|
4.063
|
100
|
406.3
|
900
|
1.10
|
1.15
|
2.30
|
1.322
|
3.622
|
100
|
362.2
|
1000
|
1.00
|
1.05
|
2.10
|
1.103
|
3.203
|
100
|
320.3
|
Total
|
5233.0 Cum.
|
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