重力式挡土墙稳定性的结构体系可靠度分析

Analysis of reliability of structural systems for stability of gravity retaining walls

重力式挡土墙结构最主要的失稳模式是倾覆失稳和滑移失稳。为了计算重力式挡土墙稳定性的结构体系失效概率,首先分别建立重力式挡土墙结构抗倾覆稳定性和抗滑移稳定性的功能函数,然后引入结构可靠度分析一次二阶矩法中的验算点法(JC法)分别对两种失效模式进行计算,得出两个相应的可靠度指标。将两种失稳模式视为串联系统,由逐步等效平面法计算结构体系可靠度指标,最后由结构体系可靠度指标计算出该挡土墙稳定性的结构体系失效概率。根据上述方法,利用MATLAB程序计算了某挡土墙,得出了结构体系可靠度指标和结构体系失效概率。

The major unstable modes of gravity retaining walls are overturning and sliding.In order to compute the failure probability of structural systems for stability of gravity retaining walls,firstly,two performance functions against overturning and sliding 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 two failure modes respectively,and two corresponding reliability indexes could be obtained.It was assume that the two failure modes formed a serial system and the reliability index of structural systems could be computed by the equivalent plane method.Finally,the failure probability 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 reliability index and failure probability of structural systems were computed by MATLAB program.