In: Civil Engineering
Hi,
Below is the solution of given problem.
To calculate the backfill volume we will follow the below steps:
Step 1
A typical cross section sketch is attached below. Since there is a slope of 1:1 (1H:1V) on both sides, the top width will be bottom width +2 time of height= 6’+17’+17’ = 40’
Given Length (L) = 185’
Average Breadth (B) = (40’+6’)/2 = 23’
Depth = 17’
Total Volume of trench = 185’x23’x17’ = 72335 cubic feet
= 72335/9 cubic yard = 8037.22 cubic yard (1 cubic yard = 9 cubic feet)
Volume of Pipe = Length x Cross Sectional Area
Dia of pipe = 36 in = 36/12 feet = 3 feet
Volume of Pipe = 185’ x π/4 x 3’2 = 1307.69 cubic feet
= 1307.69/9 cubic yard = 145.30 cubic yard
Hence, total volume of backfill = total volume of trench –volume of pipe – volume of bedding
= 8037.22-145.30-21.6
=7870.32 cubic yards [Ans]
Hope the above meets the requirement.
Waiting to hear from you soon,
Warm Regards
Saras Jain