地震力作为一种动态载荷,其作用是导致顺层结构面黏聚力及抗拉强度的丧失。由此,提出了一种动力分析法(数值分析法)与极限平衡法(公式法)相结合的顺层岩质边坡地震稳定性评价方法。该方法利用基于连续介质力学的离散元方法(CDEM)获取震后结沟面处的残余强度,将残余强度代人极限平衡公式求解重力作用下的安全系数,并将此安全系数作为评价顺层岩质边坡地震稳定性的指标。分析结果表明,传统拟静力法用于顺层岩质边坡地震稳定性的评价是不适宜的,通过本文方法获得的顺层边坡动力安全系数具有明显的3阶段特征(水平段-速降段-水平段),而拟静力法获得的安全系数随着设防烈度的增大却呈现出逐渐减小的特征。此外,所述方法还可体现地震波频率对顺层岩质边坡稳定性的影响。
The seismic load is considered as a dynamic load, which results in the loss of the cohesion and tensile strength of the structural face. A new stability analysis method is proposed based on the dynamic analysis approach and the limit equilibrium method. For getting the dynamic safety factor, the continuum-based discrete element method considered as a dynamic analysis approach is adopted to get the residual strength, and then the limit equilibrium method is used to calculate the safety factor under gravity according to the residual strength. The analysis shows that it is unsuitable using the pseudo-static method to evaluate the dynamic stability of bedding rock slopes. Three-stage feature (horizontal stage, quick-decline stage and horizontal stage) of dynamic safety factor can be obviously gotten by the proposed method, while the safety factor decreases gradually with the increase of the fortification intensity by the pseudo-static method. Moreover, the dynamic safety factor affected by the seismic frequency can also be obtained by the new method.