针对大型边坡可能具有多个滑动方向和多级滑动面的特点,提出安全度分区的方法。这种方法以强度折减理论为基础,首先选取典型边坡地质剖面建立二维数值模型,通过局部折减搜索不同深度的潜在滑动面,确定边坡的多种破坏模式,运用极限平衡法进行各个潜在滑动面的稳定性计算,即可得到边坡不同深度处的稳定性系数。然后,建立三维数值模型,并对三维模型进行各种破坏形式的局部强度折减,分析各种破坏形式下的影响范围。最后,综合分析各种破坏形式的稳定性系数及其变形破坏影响范围,对边坡进行安全度分区。以龙江特大桥基础边坡的安全度分区为例,证明这种方法对于全面刻画大型边坡的稳定状态是有效的,并可为边坡的监测设计、治理设计及施工提供指导。
According to the characteristics of large-scale slope which may have multiple slip directions and multi-level slip surfaces,the method of safety zonation is proposed. Based on the theory of strength reduction, firstly,the typical geological section of the slope is selected to build a two-dimensional(2D) numerical model. Failure modes can be detected by applying local strength reduction to the model to search the potential failure surfaces at different depths. By using limit equilibrium method for each potential failure surface,the slope stability coefficients at varied depths and levels are obtained. Secondly,three-dimensional(3D) numerical model is established to analyze the influence area of different failure modes based on the local strength reduction. Thirdly,the safety of the slope can be zoned through aforementioned comprehensive analysis of slope stability coefficients and influence areas. Finally,the method is applied to the slope of Longjiang super large bridge;and the analysis results show that this method is effective for comprehensively demonstrating the stable state of large-scale slopes. The method can also provide guideline for the monitoring design,reinforcement design and construction design of slope.