Regression Equations Of Permanent Displacements Of Seismic Slopes Subjected To Near-fault Pulse-like Ground Motions

Permanent displacement is considered as an important indicator for the study of seismic slope stability.For the sake of potential seismic hazard evaluation,a displacement prediction model was developed which is capable of estimating permanent displacement based on various geotechnical parameters of the slope such as critical acceleration,as well as seismological parameters.And traditional ground-motion models may underestimate the seismic hazard at near-fault sites where pulse-like ground motions are expected,since the effects of near-fault pulse-like ground motions are not taken into consideration,which are different from common ground motion.Therefore,this paper mainly studied quantitative identification of the ground motion with velocity pulse and the characteristics of permanent displacement induced by velocity pulse-like ground motion.Finally,an empirical model to readily evaluate seismic slope in a near-fault region was proposed.The main contents and conclusions are as follows:(1)Tens of thousands of ground motion records from the NGA-West2 database.have been collected and rearranged.And a near-fault pulse-like ground motion database has been built using 594 groups of records including three directions(in which 13 groups are without the vertical component data),using the latest identifying method for pulse-like ground motion and quantifying the pulse-like characteristics of these records.(2)Based on the distribution characteristics of seismic landslides near the fault,this paper discussed the influences pulse effects,directional difference and vertical acceleration component have on the permanent displacement of slopes,by using an improved Newmark method with consideration of the strike direction of slope and seismic loading method.Advice was proposed to fully take into consideration the influences of pulse effects(directional difference)and vertical acceleration component when calculating the permanent displacements of near-fault seismic slopes.(3)The improved Newmark method was used to calculate the permanent displacement of slopes of different strength values(critical acceleration values between 0.01 and 0.4g)induced by 555 near-fault pulse-like ground motions within 80 km from the fault.As a result,a total number of 13248 sliding displacements all larger than 0.1cm were obtained.Based on the regression statistical method,a seismic slope permanent displacement prediction model was built considering the near-fault pulse-like characteristics of ground motion.This model is simple and practical and can be used for probabilistic seismic hazard analysis in the near-fault area.