Earth Pressure Estimation of Undrained Soil–Wall Systems with Head Rotation

Abstract

Semianalytical or analytical models for calculating active and passive earth pressure coefficients for undrained soil–wall systems subjected to head rotation are rare. To fill this gap, this study proposes a semianalytical theoretical model that describes the real failure features of wall–soil systems with head rotation and under undrained conditions. A continuous velocity field (CVF) that is decomposed into circular and radial velocity components is generated to characterize the movement of undrained soils in the plastic zone. The closed-form solutions of active and passive earth pressure coefficients are formulated based on the upper-bound limit analysis (UBLA) theorem. A comparison with numerical simulations and Rankine’s theory are performed to illustrate the importance of wall movement and the contributions of undrained cohesion. The analysis outcomes demonstrate that (1) the conventional stress-based method that ignores the head rotation of walls leads to an error of earth pressure coefficients up to 15.7%; and (2) the active and passive earth pressure coefficients have linear relationships with undrained cohesion. Finally, an application to shallow excavation is conducted, showing the good performance of the proposed model.