At which structure (place) retaining wall resist passive earth pressure?

Passive earth pressure conditions are

1. Minor principle stress becomes equals to vertical stress (Hv).
2. Major principal stress becomes equal to horizontal stress(Hh).
3. Hh = Hv x Tan^2(alpha).

The moment of the wall towards the backfill, in this case, the lateral earth pressure called a passive earth pressure.

In the case of passive earth pressure,

Major principal stress = lateral pressure

Minor principal stress = vertical pressure

In this case, soil exerts a pull on a retaining wall where the inner rupture plane called as a failure plane makes at (45- fi/2) angle with horizontal.

At depth=0 , Rankines passive force= 0

If q is a surcharge load acting on backfill, then lateral pressure = K.q applied throughout the depth of retaining wall.