一种基于拉-剪破坏的边坡动力稳定性分析方法

Slope dynamic stability analysis method based on tension-shear failure

摘要:

为量化地震作用下边坡的稳定性,优化矢量和方法并计算出相应动态安全系数,基于边坡在地震作用下的破坏模式:坡顶拉裂缝和坡脚剪切裂组合形成的贯通滑动面,推导出拉-剪破坏下矢量和法的安全系数公式,通过自编程序得到边坡潜在滑动面曲线和动力安全系数,并通过算例验证方法的正确性.针对岩质边坡,利用新、旧两种矢量和方法进行动力稳定性分析,结果表明:边坡潜在滑动面会随着地震持续时间向边坡内部走移；两种方法得到的安全系数趋势一致,但拉-剪破坏模式的下滑趋势角度更大；在拉-剪破坏模式下,边坡的安全系数有所降低,其中,边坡的综合安全系数降低了3%,说明原先的方法高估了边坡的稳定性.优化后的矢量和法能够更具体地反应出边坡在地震过程中的稳定状态,为抗震设计提供更加准确的理论指导.

Abstract:

To quantify the stability of slope under earthquake action, the vector sum method was optimized and its dynamic safety factor was calculated. Based on the failure mode of slope under earthquake action, which is the combination of the slope top crack and the slope foot shear crack, the safety factor formula of the vector sum method under pull-shear failure was derived, the slope safety factor and the potential sliding surface curve were obtained by self-programming, and the method was verified by a case study. For a rocky slope with weathered layer, dynamic stability analysis was carried out by using old and new vector sum methods. Results show that the potential sliding surface of the slope would move towards the interior of the slope with the duration of the earthquake. The safety factors obtained by the two methods were consistent, but the decline trend angle of the tension-shear failure mode was larger. In the tension-shear failure mode, the safety factor of the slope decreased, and the comprehensive safety factor of the slope was reduced by 3%, indicating that the original method overestimated the stability of the slope. The optimized vector sum method could reflect the stability of slope more realistically during earthquake and provide more accurate theoretical guidance for seismic design.