地震作用下边坡稳定性分析的坐标转换法

A Coordinate Transformation Method for Evaluating Stability of Slope under Seismic Conditions

在地震作用下边坡稳定性分析中,拟静力法是将地震作用简化为水平方向或垂直方向的不变加速度作用。此加速度产生作用于不稳定体质心的地震力,根据极限平衡理论,将所有作用于潜在滑动体上的力沿滑动面进行分解,得出沿滑动面的安全系数。在拟静力法的基础上,提出一种坐标转换法,通过坐标旋转,将地震力与重力的合力转变为垂直向下的力,从而使边坡地震稳定性问题等效为经过边坡几何形态和土体容重修正后的一般静力稳定性问题,再利用比较成熟、简便的静力分析方法进行边坡稳定性分析。利用此方法可以克服传统拟静力分析的不足,并且用于水下边坡分析,将滨水边坡的拟静力分析模型转换为相应的静力分析模型,考虑地下水的流动来模拟水对边坡的动力作用。此方法对于分析水库边坡体和堰塞湖坝体的抗震稳定性问题具有一定的应用价值。

The general method for evaluating stability of slopes under seismic conditions is simple pseudo-static （PS） analysis. The PS method is generalizations of conventional limiting-equilibrium （LE） slope stability analysis in which seismic effects are represented by an additional body force that is the earthquake force as vertical or horizontal direction of the acceleration. The safety factors of the entire potential slide can be calculated according to limiting-equilibrium tlaeory. On basis of PS method, a model transformation method is put forward. Every pseudo- static slope stability problem can be transformed into an equivalent static problem with modified geometry and unit weight. The equivalency between pseudo static and static problems allows for a straightforward transfer of experience and results from the relatively mature static method into the less developed pseudo static context. This method can overcome the shortcomings of the traditional pseudo-static （PS） analysis and used in stability analysis of waterfront slope under seismic conditions. The waterfront slope of the seismic stability model can be converted to the corresponding static model of stability and the flow of water can simulate the dynamic force of water on the slope. It is useable to evaluate stability of slope in reservoir and Barrier Lake.