Seismic response of loess-mudstone slope with bedding fault zone: Fid-Bau Portal

Seismic response of loess-mudstone slope with bedding fault zone

Huang, Qiangbing / Jia, Xiangning / Peng, Jianbing / Liu, Yue / Wang, Tao

Abstract The characteristics of dynamic responses and the failure mechanism of a loess-mudstone slope with an embedded fault zone subjected to seismic loadings were investigated by shaking table test on a scaled slope model and numerical simulation. The model was subjected to seismic ground motion excitations of increasing peak accelerations. The results demonstrated clear amplification effects to the ground acceleration at the slope surface and fault zone, which directly aggravated slope failure. Similar amplification effects were observed at the hanging wall, and this became very apparent when the peak ground acceleration exceeded 0.3 g. The dynamic response of vertical earth pressure was positively correlated with the thickness of the overburden strata under all peak accelerations. The dynamic responses of horizontal earth pressure were strongest at the top of the fault zone under peak accelerations of all levels. The dynamic responses of acceleration and earth pressure in slope both increased with rising peak accelerations. The mode of failure of the loess-mud slope with a dip bedding fault zone under the action of seismic waves was characterized as a shock slip failure. The width of the fracture distribution area in the loess-mud slope induced by seismic waves on the hanging wall was 2.5 times that of the footwall of the fault zone, which was further evidence that a slope with a dip bedding fault zone experiences an amplification effect on the hanging wall of the fault zone.

Highlights • Acceleration amplification effects at slope surface, fault zone and hanging wall are revealed. • The dynamic response of vertical and horizontal earth pressure is presented. • The dynamic response characteristics of acceleration changing with earthquake wave amplitudes are disclosed. • The failure mechanism and characteristics of earthquake-induced sliding failures are demonstrated. • The characteristics of fracture distribution area of the hanging wall and foot wall are illustrated.