A Primary Study Of Seismic Dynamic Response Of Slopes Considering The Topography,Geology And Source Effect

Earthquake induced landslides are one of the common earthquake disasters in mountainous areas.Landslides often cause a large number of casualties and property losses in related areas,directly or indirectly.The seismic response rule of the slope under the influence of ground motion is the primary issue for studying the study of slope dynamic stability.The purpose of understanding the principle of the seismic response rules of the slope is to clarify the response distribution of the slope under the action influence of the seismic wave.The site effect,geological effect,and focal source effect are three important factors influencing slope dynamic response.This paper conducted a study concerning the slope dynamic rules considering these three effects,by using numerical simulation method.(1)Site effect: Groups of slope models with different slope height,slope angle and slope shape are built to study site effect.Typical real seismic waves were loading to the slope models to study the dynamic response.Results show that with the increasing of slope height,the PGV magnification ratio increases gradually.On the contrary,the PGA magnification ratio has no such rules.With the increading of slope angle,the magnification ratio of both PGA and PGV inclines to increase.The effect of slope shape on the PGA magnification ratio is significant,however on the PGV magnification ratio is not that obvious.(2)Geological effect: Slope models with weak layers were built to study the influences of weak layer properties have on the slope dynamic response under different ground motions,by loading real seicmic waves to the models.Results show that the ground motion magnification effect of slope models with weak layers is quite different from that of slope models with homogenous material properties.The acceleration increases grantly over the weak layer due to the existence of the weak layer.The strength of the weak layer also influences the slope dynamic response.Weaker the weak layer materials,stronger the response of slope layers over the weak layer.Conclusions above agree with the study results of craking mechanisms of real seismic landslide cases with weak layers.(3)Source effect: Pulses extraction on the typical real pulse seicmic recordings was conducted by using pulse identifying and extracting methods.Three groups of seismic loadings: original recordings,pulse recordings extracted and the residual recordings are put into the models to study effects different kinds of recordings have on the seismic slope dynamic response.The simulation results show that when the natural vibration period of the slope model is close to the pulse period of the ground motion,the lowest pulse component of PGA comes out to be the main factor on the dynamic response and failure of the slope model.The conclusion further explains the significance velocity response analysis has on the study of slope dynamic response.It also clarifies the relations between long period pulse seismic recordings and near-fault large-scale landslides(with high natural vibration period)during recent years.