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Road earthwork, formation level at 150 m

Short answer

Earthwork in cutting = 1,786.15 m³; earthwork in filling = 187.07 m³.

Find out the quantity of earth work of a portion of road to be constructed with the following data: Formation width of the road = 10 m. Side slopes in banking and cutting = (2:1) and (1:1). Downward grade 1 in 120 from distance 90 to 120 m while it remains in level from distance 120 to 180 m and again upward grade 1 in 90 from distance 180 to 210 m. The formation level at distance 150 m = 1197.50.

R.L. of ground1198.651196.401199.301200.401198.10
Distance (m)90120150190210

Given data and assumptions

  • Formation width B=10B = 10 m; banking slope 2:12:1, cutting slope 1:11:1. Ground is level across the road. Stations are at 90, 120, 150, 190 and 210 m (spacing 30, 30, 40, 20 m).
  • Formation level at 150 m is 1197.50 m; level from 120 m to 180 m; falling 1 in 120 from 90 to 120 m, so level at 90 m = 1197.75 m; rising 1 in 90 from 180 m, so level at 190 m = 1197.50 + 10/90 = 1197.611 m and at 210 m = 1197.833 m.

Method

Level (plain-ground) sections are used. With centre height hh, formation width BB and side slope s:1s:1:

A=(B+s h) hA = (B + s\,h)\,h

Volume between two sections = mean area × distance; where a section changes from cutting to filling, the length of each part is found by proportion of the depths and the volume of each part = ½ × end area × length.

ChainageGL (m)FL (m)Depth of cutting / height of filling (m)
0+0901,198.6501,197.750cutting 0.900
0+1201,196.4001,197.500filling 1.100
0+1501,199.3001,197.500cutting 1.800
0+1901,200.4001,197.611cutting 2.789
0+2101,198.1001,197.833cutting 0.267

Sectional areas

ChainageCentre ht. hh (m)Cutting area (m²)Filling area (m²)
0+090cut 0.909.8100.000
0+120fill 1.100.00013.420
0+150cut 1.8021.2400.000
0+190cut 2.7935.6670.000
0+210cut 0.272.7380.000

Volumes

BetweenDistance (m)Cutting (m³)Filling (m³)
0+090 – 0+12030.066.22110.71
0+120 – 0+15030.0197.7576.36
0+150 – 0+19040.01,138.140.00
0+190 – 0+21020.0384.050.00
Total120.01,786.15187.07

Answer: Earthwork in cutting = 1,786.15 m³; earthwork in filling = 187.07 m³.

✓ Answer checked by Claude Opus 5.5 (high effort)

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