Passive earth pressure under various modes of wall movement: a numerical approach

Numerical computations using an explicit-finite difference code were carried out to evaluate the passive earth pressure magnitude and distribution against a retaining wall subjected to different wall movement modes: translation (T), rotation about the bottom (RB) and rotation about the top (RT). In agreement with classical solutions, the results showed that, in T mode, passive earth pressure distribution was substantially hydrostatic with depth for all the wall displacement stages. However, when either RT or RB was considered, a clear non-linear distribution that was strongly affected by the wall displacement magnitude was noted. For the RT mode, due to the arching effect, the increase in earth pressure behind the lower half of the wall was more pronounced, with the wall displacement hardly affecting the centroid of the passive load distribution located below the commonly used one-third of the wall height. In RB mode, as wall rotation progressed, the passive earth pressure mobilised in upper part of the wall increased and its distribution gradually changed from a non-linear to linear distribution. Compared with previous experimental results available in the literature, it was found that mobilised passive earth pressure in RB and RT modes needs more displacement than in the T mode.