雨水渗透下节理岩质边坡失稳离散元模拟

Simulations of Joint Rock Slope Failure Under Rainfall Infiltration via DEM

采用一种新的能够考虑水软化与化学风化作用的复合微观接触模型,将其植入离散元软件PFC2D中,进行节理岩质边坡失稳过程的模拟.建立一个85°倾角并含有3组倾角为45°节理的岩质边坡,采用重度增加法研究岩质边坡在水软化及化学风化影响下的破坏过程.结果表明:边坡滑动过程中,应力应变波动较大,不同位置处的应力应变的波动具有相似的规律;滑动体的速度达到一定值时,才开始产生比较明显的位移;速度及位移快速增加的时刻晚于应力应变开始波动的时刻;岩质边坡的破坏主要为岩桥贯通,破坏面为节理滑动面,颗粒间主要为拉剪破坏与压剪破坏,破坏阶段拉剪破坏速率大于压剪破坏.

A new compound micro-connect model, which considered the water softening and chemical weathering effects, was implanted into DEM software-PFC2 D to simulate the failure process of joint rock slope. The rock slope was modeled with three groups of joints, and the failure process was simulated by the gravity increase method, where the water softening and chemical weathering effects were taken into account. The results showed that the fluctuations of stress and strain, which were similar at different positions, were significant during the failure process. The obvious displacement was occurred after the speed of sliding body run up to a certain value. The time, when the speed and displacement increased rapidly, was later than the time that stress and strain began to fluctuate. The failure of rock slop was mainly due to the break of rock bridges, sliding along the joint surface. The failure modes between particles were mainly compression-shear and tension-shear failure, and the rate of tension-shear failure was greater than that of compression-shear failure.