Extended Pseudodynamic Method to Assess Seismic Active Pressure under Seismic Loading

Abstract

Seismic stability of geotechnical structures is an essential issue in earthquake geotechnical engineering. The pseudostatic method is the most common method for seismic stability analysis of geotechnical structures. The pseudodynamic method was developed, considering the phase differences and time effects; however, it does not satisfy the zero stress boundary conditions at the surface. A modified pseudodynamic method was proposed according to the zero stress boundary conditions for harmonic base motion. In the formulation of the modified pseudodynamic method, the ground motion of an earthquake with its frequency content is not considered. Also, the imaginary part of the response related to the damping effect is removed, making it more difficult to develop than expected. The pseudostatic and pseudodynamic methods are overestimated because the failure wedge is determined similar to the static method. This study aims to propose a new pseudodynamic method for seismic analysis of geotechnical structures considering the earthquake ground motion and both the real and the imaginary parts of the response. New transfer functions are introduced to obtain inertial forces and seismic active pressure based on the input motion. Furthermore, according to the experimental observations and momentum theory, a new method is proposed to determine the critical failure surface accurately. A comparison with a few experimental and analytical results in the literature is also presented. The results of the proposed method are in good agreement with the experimental and analytical results. Finally, an example is provided to illustrate the application of the proposed method. The effects of shear wave velocity and wall height on the seismic active pressure during an earthquake are investigated.