Study on instability and damage of a loess slope under strong ground motion by numerical simulation
Study on instability and damage of a loess slope under strong ground motion by numerical simulation
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DOI：
10.1016/j.soildyn.2021.107050
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发表时间：
2021-11-17
影响因子：
4
通讯作者：
Peng, Da
中科院分区：
文献类型：
--
作者：
Chang, Chaoyu;Bo, Jingshan;Peng, Da
强地震动作用下黄土边坡的失稳破坏是一个复杂的过程，包括滑动、平移和旋转，这使得离散单元法成为模拟这一过程的合适理论。因此，本文采用颗粒流程序（PFC）模拟黄土滑坡在强震动作用下的失稳破坏过程。在现场调查和室内试验的基础上，对细观参数进行了详细的标定，并建立了二维模型。结果表明，坡面对地震动有放大作用，导致坡面土体产生强烈的振动。坡肩是地震加速度放大系数最大的部位，是边坡失稳破坏的关键。在地震力作用下，边坡上部首先发生拉张破坏，下部发生堆积破坏，最终形成剪切出口。相应地，傅立叶频谱的高频分量随着边坡的破坏而增加。本研究强调了第一主应力和第三主应力之间的差异逐渐增大，破坏了颗粒之间固有的粘性胶结物，这是强震下边坡破坏的主要原因。
The instability and damage of loess slopes under strong ground motion can be a complicated process, involving sliding, translation, and rotation, which makes the discrete element method as a suitable theory to simulate such a process. Therefore, in this study, the particle flow code (PFC) is developed to simulate the instability and damage process of the loess landslide under strong motion. Based on field investigations and laboratory tests, the detailed identification of mesoscopic parameter was calibrated, and a 2D model was established. The results show that the slope surface tends to amplify the ground motion, resulting in the strong vibration of the soil on the slope surface. The slope shoulder is the position with the largest amplification coefficient of seismic acceleration, which is the key to the instability and failure of the slope. And, under the seismic force, the tensile failure firstly occurs in the slope upper part, and then the accumulation failure occurs in the lower part, finally a shear outlet is formed. Accordingly, high-frequency component of the Fourier spectrum increases with the slope failure. This study highlights the gradual increase in the difference between the first principal stress and the third principal stress, which destroys the inherent cohesive cements between particles, which is the main cause of slope failure under strong motion.