顺层岩质边坡地震动力响应及地震动参数影响研究

 利用FLAC2D建立顺层岩质边坡模型，分析其在地震作用下的动力响应规律，研究地震动参数对其动力响应的影响。结果表明：顺层岩质边坡在地震作用下失稳主要由结构面控制，位移主要发生在潜在滑移面上部岩体中；对地震波存在垂直向和临空面放大作用，其滤波作用没有土质边坡明显，不同岩层会对某一频率的波产生明显的放大效应；当振幅、卓越频率增加时，坡肩下方的加速度放大系数呈递减趋势，且在强度相对较低的岩体内较明显，但随着振幅增加，边坡动力响应增强；各处加速度放大系数受地震动持时影响较小，剪应变增量受其影响较大。当振幅、持时增加时，边坡位移呈增大趋势；当卓越频率增大时，边坡位移减小。同时，证实了地震边坡破坏由上部拉破坏与下部剪切破坏组成，研究结果有助于进一步揭示边坡在地震作用下的失稳机制。

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.