基于验算点法的重力式挡土墙结构可靠性分析

Analysis of Reliability of Gravity Retaining Walls Based on JC Method

重力式挡土墙结构最主要的失稳模式是滑移失稳、倾覆失稳和地基承载力失稳。该文对重力式挡土墙结构的3种失稳模式进行分析,建立对应的可靠度分析模型,引入结构可靠度分析一次二阶矩法中的验算点法(JC)法分别对3种失效模式进行可靠度分析,得出相应的可靠度指标及其失效概率。将3种失效模式视为串联系统,由结构体系稳定性分析中的宽界限法近似计算挡土墙结构的体系失效概率。根据上述方法,利用Matlab编制相应的程序计算了某个挡土墙的实例计算,得出了该挡土墙结构失效概率的界限,同时对其进行了参数敏感性分析。

The major unstable modes of gravity retaining walls are overturning, sliding and the instability of the foundation bearing capacity. In order to compute the probability of failure of gravity retaining walls, firstly, three performance functions against overturning, sliding and the instability of the foundation bearing capacity of gravity retaining walls were established. Then, the first-order second-moment theory in structural reliability analysis, i.e., the checking point method （JC method） was introduced to compute the three failure modes respectively, and three corresponding reliability indexes could be obtained. It was assumed that the three failure modes formed a serial system and the reliability index of structural systems could be computed by the wide boundary method. Finally, the probability of failure of structural systems for stability of the retaining walls could be computed by the reliability index of structural systems. Taking a practical gravity retaining wall for an example, the boundary of structural systems was computed by MATLAB program, and the analysis of parameter sensitivity was done for proclaiming the influence of variable coefficient of parameters.