Question

Consider the following statements:

Which of these statements is/are correct?

• A. 1 alone
• B. 1 and 2
• C. 2 alone
• D. 3 alone

Answer 1

The correct option is D 3 alone

(d) By considering the wall friction, the Coulomb's theory eventually considers the wall to be rough. The relative movement of the wall and the soil on the back develops frictional forces that influence the direction of the resultant pressure.
In Coulomb's theory, the failure surface is assumed to be plane surface which passes through heel of the wall. This assumption introduces only a negligible error in the case of active pressure. However in the case of passive pressure,the involved remains small only for values of $\sigma$ less than $\varphi /3$.