STUDY OF DYNAMIC RESPONSE OF BEDDING ROCK SLOPE UNDER EARTHQUAKE AND INFLUENCE OF GROUND MOTION PARAMETERS

A model of bedding rock slope is established using FLAC2D program,and the dynamic response laws and the influence of parameters of ground motion on the dynamic responses under earthquake action are analyzed.It is shown that the structural surface plays a main control role on the failure of bedding rock slopes,displacement mainly takes place in the rock mass which on the potential sliding surface.The seismic waves are amplified by the vertical direction and free face of the slopes;and the filter function of bedding rock slope is not as apparent as soil slope.Different rock formations produce a significant amplification at certain frequency.The amplification coefficients of acceleration below the crest of slope decrease when the amplitudes and frequencies of seismic waves increase.The phenomenon is obvious in rock mass with relatively low intensity,but the dynamic response of slope becomes serious.The amplification coefficients of acceleration are less affected by the duration,while the duration has a great influence on the shear strain increment.The maximum displacement of the slope evidently increases with the increasing amplitudes and duration of earthquakes ground motion,while the maximum displacement of the slope decreases with the increase of predominant frequencies.It is approved that the failure of slope under earthquake action consists of the tension failure in the upper part and the shear failure in the lower part.The study results are helpful to further researches on the mechanism of slope instability under earthquakes action.