关键词: 边坡, 地震波, 动力特性, 放大系数, 软弱夹层, DDA, 透射系数

Abstract: In order to analyze the dynamic response of slope, we establish a slope analysis model by using improved DDA(discontinuous deformation analysis), and obtain contours of acceleration amplification coefficient in slope body. First of all, we verify that viscous boundary distance has minimal effect on dynamic response characteristics of slope. Secondly, we analyze the changes of amplification coefficient with elevation and depth in the presence of different slope angles, slope heights, lithology, periods of seismic wave, etc. Analysis shows that, 1) if slope angle or slope height is smaller than a certain value, amplification coefficient increases with elevation and depth; 2) harder rock or longer period of input wave will lead to bigger amplification coefficient; 3) in case of adverse geological bodies such as joint and weak interlayer, seismic wave propagation will be influenced by reflection and transmission, thus affecting dynamic response characteristics of slope. On the basis of DDA, we can find the following results. Big elastic modulus is in favor of transmission effect of joint on wave propagation. When the ratio of joint spacing to input wave length is smaller than critical value, the greater the ratio is, the stronger the effect of joint on transmission wave is. If rock under interface is harder than that above the interface, and when the difference between two elastic modulus increases, the reduction of peak acceleration in transmission wave gradually tends to be obvious. On the contrary, the reduction will be changed into amplification. When weak interlayer thickness or ratio of the thickness to acoustic impedance in surrounding rock is bigger, transmission effect of seismic wave through weak interlayer is smaller.

Key words: slope, seismic wave, dynamic characteristics, amplification coefficient, weak interlayer, DDA, transmission coefficient