Seismic passive earth thrust of submerged backfill with two-dimensional steady seepage

HUANG Rui(黄睿)^{1, 2, 3}, XIA Tang-dai(夏唐代)^{1, 2}, LIU Zhi-jun(刘志军)^{1, 2}

(1. Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education,
(Zhejiang University), Hangzhou 310058, China;
2. Research Center of Coastal and Urban Geotechnical Engineering, Zhejiang University, Hangzhou 310058, China;
3. China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, China)

Abstract:To investigate the seismic passive earth thrust with two-dimensional steady seepage, a general pseudo-dynamic solution was established based on the limit equilibrium analysis. This solution was purposefully applied to a waterfront gravity wall, which retains a submerged backfill with a drainage system along the backfill-structure interface. The wall was assumed to move towards the backfill to the passive failure state. And the theoretical derivation considered the pore pressures induced by the seepage, the excess pore pressures generated by the earthquake and the seismic inertial forces. Thereinto, the hydrostatic and hydrodynamic pressures were calculated by the analytical formulas, while the seismic forces were obtained by the pseudo-dynamic method. In the parametric study, the results indicate that the velocity of shear wave has a more prominent impact on the seismic passive earth thrust than that of primary wave. Both the horizontal and vertical seismic actions decrease the passive earth pressure, but the horizontal one affects the amplitude of the earth pressure coefficient more significantly. Moreover, the soil friction and the wall friction distinctly increase the seismic passive earth pressure just like the static situation. The comparison shows that the results are consistent with the previous work, which verifies its validity.

Key words:earth pressure; earthquake; pseudo-dynamic method; seepage