顺层挖方边坡松弛区及稳定性数值模拟分析

为有效的研究砂泥地互层的顺层坡体在人类开挖工程影响下的失稳特征,本文以山西省长晋高速公路K31+160~K31+460段顺层滑坡为例,通过Geo-slope软件数值模拟了该顺层坡体在边坡开挖后,防护工程没有及时对坡体损失的稳定度进行补偿,造成坡体的自身锁固作用削弱,使坡体在自身势能作用下发生的松弛范围,及坡体沿处于塑性变形区的软弱层发生滑动变形的特征进行了数值模拟;并根据后续工程为有效的补偿或提高坡体的稳定性,根据施做工程对坡体的位移、应力等进行有效限制、防止坡体由于蠕变及松弛而导致坡体中塑性区出现直至贯通的情况进行了有效的数值模拟。依据8年来坡体的良好稳定性证明,通过数值模拟指导顺层挖方边坡的工程治理是有效的,对顺层挖方边坡松弛区及坡体在工程加固前后的稳定性数值模拟分析是合理的,可行的。

Numerical Simulation Analysis on Relaxation and Stability of the Cutting Bedding Slope

In order to study the instability characteristics of dip slope composed of sandstone and mudstone alternation under the influence of human excavation, one bedding-plane-controlled landslide, located at the K31+160 ~ K31+460 section of Chang-Jin expressway in Shanxi province, was presented in this paper. Firstly, the relaxation region characteristics of the dip slope without timely reinforcement after excavation including relaxation of slope under potential energy due to weakening the locking effect and sliding of the slope along the weak layer in area of plastic deformation was simulated with Geo-slope software. And then, the stability of the dip slope was simulated again after its reinforcement. According to the simulated results of the dip slope after reinforcement, it can be seen that the support system can reduce the displacement and stress of slope effectively to avoid plastic area formation in slope due to creep and relaxation. Based on the proves in practices in recent 8 years, it is confirmed that numerical simulation is a efficient way in guiding dip slope excavation projects, and it is reasonable and feasible through making use of numerical simulation to analyze the relaxation region of excavating bedding slope, and stability of slop before and after reinforcement.