Permanent displacement reliability analysis of soil slopes subjected to mainshock-aftershock sequences

Abstract

It is of great significance for disaster prevention to study the influence of mainshock-aftershock sequences on reliability of the soil slope. Considering the uncertainty of the mainshock-aftershock sequences, a new analysis method is proposed for the random dynamic response analysis and permanent displacements reliability evaluation of soil slopes under the action of mainshock-aftershock sequences. Firstly, a simulation method of random seismic sequence based on Copula function considering the correlation between mainshock and aftershock is introduced in this paper. Then, the permanent displacement of soil layered slope under 86 randomly generated mainshock-aftershock sequences and single mainshocks is calculated based on Newmark method. And the influence of aftershocks on the permanent displacement of slope is analyzed through the mean value. Besides, the influence of peak ground acceleration (PGA) on the permanent displacement and sliding surface of slope is also discussed. Finally, based on the probability density evolution method (PDEM), the influence of aftershocks on the permanent displacement reliability of slope is explained from the perspective of probability for the first time. The results show that the randomly generated mainshock-aftershock sequence can meet the needs of random dynamic analysis and probability analysis of soil slope by comparing with the target value. Based on the random dynamic calculation results, compared with single mainshocks, the soil slope has larger permanent displacement under the mainshock-aftershock sequences. However, there are obvious uncertainties in the permanent displacement and the position of the most dangerous sliding surface according to the different soil layer distributions and ground motions. It is very necessary to study the influence of mainshock-aftershock sequence on slope reliability from the perspective of probability. When the threshold is 1 m, the reliability of the slope will be reduced by 2 %∼15 % by aftershocks.