基于有限元的动力稳定性评价方法与应用——以王家墩古滑坡为例

天水市秦安县王家墩滑坡为宝兰客专沿线巨型古滑坡群，秦安隧道穿其而过。笔者以王家墩古滑坡为研究对象，围绕其工程中静、动力抗滑稳定问题，通过室内试验对影响王家墩古滑坡稳定性的地质构造、场地工程条件等内在因素进行分析评价，在此基础上通过有限元动力分析，对王家墩古滑坡在地震载荷下的动力响应进行分析，明确王家墩古滑坡稳定的影响因素、地震荷载与滑坡失稳破坏间的关系。采用动力有限元法和强度折减法结合的方法，开展动力抗滑稳定分析方法研究。分析结果表明，地震作用时的水平推力对古滑坡的稳定性有很大影响，表现为上部坡体的整体滑移和隧道入口段黄土堆积层局部失稳滑塌，采用位移突变的方法来确定边坡动力失稳及动力安全系数。

Evaluation Method and Application of Dynamic Stability based on Finite Element Analysis: Example from the Wangjiadun Landslide in Tianshui City,Gansu Province

The Wangjiadun landslide in Qinan County, Tianshui City is a huge ancient landslide group along the Baoji-Lanzhou High-speed Railway, with the Qinan tunnel passing through it. By taking Wangjiadun ancient landslide as the studying object and centering on its static and dynamic anti-sliding stability, the intrinsic factors, such as geological structure and site engineering conditions, has been analyzed and evaluated in this paper, which affect the stability of Wangjiadun ancient landslide through indoor and field test. And then, the dynamic response of Wangjiadun ancient landslide under earthquake load has been analyzed by finite element dynamic analysis method, and the relationships between the stability factors influencing, earthquake load and landslide instability & failure under earthquake load for the Wangjiadun ancient landslide have been defined. In addition, the study on dynamic anti-sliding stability analysis has been carried out by using the dynamic finite element method combined with strength reduction method. The results show that the horizontal thrust under earthquake action has a great influence on the stability of Wangjiadun ancient landslide, which is manifested as the overall slip of upper slope and the local instability collapse of loess accumulative formation at the tunnel. Therefore, the method of displacement catastrophe can be used to determine the dynamic instability and dynamic safety factor of the slope.It is manifested as the overall slip of upper slope and the local instability adn collapse of loess accumulative formation at the tunnel. Therefore, the method of displacement catastrophe is used to determine the dynamic instability and dynamic safety factor of the slope.