Question

The resultant active pressure per unit length of wall for dry backfill with no surcharge acting  at _________ above the base of wall.

(a) H/2

(b) H

(c) H/6

(d) H/3

The question was posed to me in class test.

I would like to ask this question from Active Earth Pressure: Rankine’s Theory topic in portion Failure Envelopes & Earth Pressure of Geotechnical Engineering II

Answer 1

The correct answer is (d) H/3

Explanation: The pressure distribution of the stresses in the retaining wall due to the backfill is triangular one. Since the pressure distribution is triangular, the resultant active pressure per unit length of wall will act at the centroid of the wall, which is at a distance of H/3 from the base of the wall.