反倾软硬互层岩体边坡地震响应的数值模拟研究

反倾软硬岩体互层边坡是公路建设中经常遇到的一类边坡,在不利条件下有失稳破坏的可能,特别是在坡脚受到扰动、降雨、地震等作用时.以“5.12”地震期间都汶公路(都江堰—汶川)上一处边坡的地震响应为例,采用离散元UDEC软件对其进行模拟,系统研究了其地震响应的变形破坏机制.研究结果表明,地震作用下,软弱岩层挤压变形强烈,有向外剪出的趋势.同时,在地震波反复拉张作用下,软弱岩层位置容易开裂,成为坡体变形破坏的优势拉裂区域.地震波加速度、速度随高程变化放大显著,在坡体表部位移最随高程增高而逐渐增大.就整体而言,岩体内部的节理裂隙进一步张开,井产生了一些新的裂隙,弯曲倾倒有加剧的趋势；而坡表覆盖层普遍具有表部拉张开裂和掉块现象,特别是在地形几何形态突变处,破坏更为显著.

Numerical simulation of seismic response of anti-dumping rock slope interbedded by hard and soft layers

A kind of anti-dumping rock slope interbedded by hard and soft layers are often encountered in highway construction.In adverse conditions,the stability of the slope may be lost,especially under certain conditions such as disturbed slope toe and effect of rainfall and earthquake,etc.This paper takes the earthquake response of Shawozi slope during the 5.12 Wenchuan earthquake as an example,which is located in Duwen road(Dujiangyan-Wenchuan).The discrete element software UDEC is used to simulate and systematically study the seismic response of deformation and failure mechanism.The results show that,under the earthquake,the soft and weak rock is squeezed and cut out from the slope with strong deformation.At the same time,in soft rock locations,it is easy to crack under the repeated tensile influence of seismic waves,and become the advantage area of deformation and failure of the slope.The amplification coefficient of acceleration and speed changes significantly with elevation.The displacement in the slope gradually increases with increasing elevation.On the whole,the joints and fissures inside the bend-dumping rock mass further open,and a number of new cracks are produced so that there is an increasing trend in dumping bent.The phenomena generally appear in the slope cover-layer including the tensile cracking and block dropping,especially at the mutation position of terrain geometry,and the damage extent is more significant.