Seismic Active Earth Pressure for Soils with Tension Cracks

Abstract

It is widely acknowledged that the occurrence of seismic force and cracks will increase the active earth pressure acting on a retaining wall. In this work, a kinematic approach for the evaluation of seismic active earth pressure was established, and a rotational mechanism consisting of a logarithmic spiral curve and a vertical crack was used to calculate the rates of external work and internal energy dissipation. Although numerous cracks exist in cohesive backfill, this study only considered the most critical vertical crack that led to the maximum active earth pressure. Different crack types, including pre-existing cracks and cracks forming contemporaneously with the mechanism, are discussed in the paper. According to the quasi-static method, the concept of seismic coefficient was adopted to account for earthquake effects on the active earth pressure. In the domain of soil plasticity, explicit expressions of seismic earth thrust for different cracks types were derived. A comparison analysis was carried out to verify the effectiveness of the present calculations. The influence of different parameters on the seismic earth pressure is discussed. It was found that the presence of cracks and the seismic actions have adverse effects on the stability of soil–wall systems, and that the pre-existing cracks always yield a more conservative result than the formation cracks.