Seismic External Stability Analysis of Geosynthetic-Reinforced Earth Structures Using an Integrated Analytical Approach

摘要

External stability analysis of geosynthetic-reinforced earth structures (GRESs) under seismic loading conditions requires calculation of the total (i.e., static and seismic) thrust acting on the retained soil mass. The total thrust is used to assess sliding and eccentricity of the earth structure. Current guidelines for seismic design of GRESs recommend using the Mononobe-Okabe (M-O) method or the Generalized Limit Equilibrium approach to determine the total thrust. This paper presents a seamless extension of the M-0 method by developing an integrated analytical formulation which determines the dynamic active earth pressure coefficient for any batter representing unstable slopes. The analytical formulation is developed for simple, homogeneous, cohesionless slopes using a pseudostatic limit equilibrium approach assuming a potential failure along a log spiral trace. Parametric studies are performed and the results are presented in a series of charts. The charts can be used to determine the dynamic active earth pressure coefficient (and the total thrust) for different design angles of friction and also various geometrical parameters of GRESs. The results from the proposed method are compared with those obtained from the M-0 method and Limit Analysis method. While the M-0 method and its pertinent planar failure surface prevail for a vertical GRES with uniform reinforcements, the presented approach provides more critical results for flatter GRESs where the active wedge is augmented by a curved failure surface. The application of the proposed method is illustrated in a design example, where the external stability of a GRES is evaluated using the total thrust calculated from the proposed method.