反倾层状结构岩质边坡动力响应特性及破坏机制振动台模型试验研究

 采用物理模型试验，研究强震作用下反倾层状结构岩质边坡动力响应特征及破坏过程。试验结果表明：(1)加速度放大系数具有随坡高而增大，且越接近坡顶放大越明显的非线性高程效应及越接近坡表放大越强烈的非线性趋表效应。(2) 基本以3/4坡高为界，此高度以上，边坡水平加速度放大效应明显高于垂直加速度，而此高度以下，垂直加速度放大效应较明显。(3) 地震波频率对加速度放大系数影响最大，当地震波频率越接近坡体自振频率时，加速度放大越明显，且边坡出现波动特性的坡高越低。(4) 加速度峰值不改变动力加速度放大系数在坡体内的分布，但加速度峰值越高，边坡动力加速度放大系数越大。(5) 反倾层状结构边坡在地震力作用下的破坏过程主要为：地震诱发→坡顶结构面张开→坡体浅表层结构面张开→浅表层结构面张开数量增加、张开范围向深处发展，且坡体中出现块体剪断现象→边坡中、上部及表层岩体结构松动，坡体内出现顺坡向弧形贯通裂缝。试验中出现的变形分带现象进一步证明了动力加速度放大系数在坡体内分布的非线性。

SHAKING TABLE MODEL TEST ON DYNAMIC RESPONSE CHARACTERISTICS AND FAILURE MECHANISM OF ANTIDIP LAYERED ROCK SLOPE

Dynamic response characteristics and failure process of antidip layered rock slope under strong earthquake are studied by large-scale shaking table model test inputting sine wave in X-direction and XZ-direction. Testing results show that：(1) Acceleration amplification coefficients increase nonlinearly with the increase of slope height. The slope has the nonlinear height effect，i.e. more obvious of amplification more closing to slope top，and nonlinear surface effect，i.e. more intensity of amplification more closing to surface. (2) 3/4 of slope height is the critical height. Horizontal acceleration is amplified more obviously than vertical acceleration while above the height；but when below the height，the vertical acceleration is amplified more obviously. (3) The effect of frequency of seismic wave on the acceleration amplification coefficients is the largest. While the seismic frequency approaches to slope body?s natural frequency，the amplification effect is more obvious and the critical height is lower. (4) The amplitude of acceleration has no influence on distribution of its amplification coefficients in slope；but the larger the amplitude of acceleration is，the more the amplification coefficient is. (5) Failure process of the antidip layered rock slope under earthquake is divided into the following stages：earthquake induction；opening of structural surface at the top of slope；opening of structural surface at slope surface；increases of opening number of surface structural surfaces and depth of opening range，model blocks shearing broken at inner slope；rock structure loose at upper part and slope surface and arc transfixion crack along slope appearing. The zonal deformation phenomenon in the test has testified that distribution of acceleration coefficient in slope body is nonlinear.