黄土高边坡的三维动力稳定性分析——以固原九龙山边坡为例

针对高烈度区九龙山黄土高边坡的动力稳定性问题,调查分析了该边坡的工程地质条件和场地所在区域构造活动与分布特征。在考察动荷载循环、往复作用下黄土反应敏感性及动强度参数,以及沿坡高确定地震惯性力反应地震作用大小的基础上,将强度参数折减与有限差分方法结合,从而形成了边坡的拟静力强度折减有限差分分析方法。通过九龙山土边坡拟静力强度折减三维有限差分法计算分析,得到了强度折减条件下边坡的位移场和应力场,边坡关键点位移与折减系数之间的关系,以及黄土高边坡的动力稳定性安全系数。其分析结果与传统的二维极限平衡分析方法确定的结果基本一致,验证了边坡拟静力强度折减有限差分方法的合理性。

Three-dimensional dynamic stability analysis of high loess slope taking the jiulongshan slope for example

In this paper, the geological conditions, regional tectonic activity and its distribution characteristics of Jiulongshan high loess slope located in high seismic intensity region were firstly analyzed, and then the dynamic stability of Jiulongshan high loess slope was evaluated by a new quasi-static method. Based on analyzing the sensibility of dynamic response and strength law of loess subjected by the cyclic loading and determining the earthquake the seismic inertia force along the slope height indicating the size of the earthquake, a finite difference based quasi-static strength reduction analysis method has been proposed by combining the strength reduction method and the finite difference method. Through the new method analyzing the Jiulongshan loess slope, the displacement and stress distributions of the slope, the relationship between the displacement at key points and the reduction coefficient as well as the dynamic stability safety factor of the high loess slope were obtained. The results agreed quite well with the solutions obtained by traditional two-dimensional limit equilibrium analysis method. It confirms the accuracy of the new quasi-static strength reduction method based on finite difference approach.