Earthwork Calculations MCQ with answer and solution

Concept

In the mean depth method, the mean depth is the average of the depths at two consecutive sections.

Formula

d_m = (d₁ + d₂)/2; A = (B + s d_m) d_m; V = A × L

Step-by-step solution

1. Take the depths at two consecutive sections: d₁ and d₂. 2. Mean depth d_m = (d₁ + d₂)/2. 3. This is averaging of the two depths. 4. Find the area using d_m, then volume = area × distance between sections. 5. So the answer is B.

Explanation

In earthwork estimation by the mean depth method, we take the average of the depths at two consecutive sections. We then use this mean depth to find the cross-section area. Volume equals this area times the length between the sections.

Why the other options are wrong

A: Subtracting gives the difference in depth, not the mean. C: Adding gives only the sum; it must also be divided by 2. D: Multiplying the depths has no meaning for mean depth.

Shortcut

Mean means average: (d₁ + d₂)/2.

Common mistake

Choosing 'adding' and forgetting to divide by 2.