基于随机响应面法的基坑地连墙可靠度分析

Reliability Analysis of Diaphragm Wall in Foundation Pit Based on Stochastic Response Surface Method

基于随机响应面法和ABAQUS有限元软件,建立了基坑地连墙最大侧向位移的随机响应面函数,得到地连墙的功能函数,对随机响应面进行了拟合精度验算,基于随机响应面法对地连墙进行可靠度分析.结合基坑工程实例,利用随机响应面法计算了支护结构的可靠指标,并且对比分析了土体参数的随机性对随机响应面拟合精度和结构可靠指标的影响.结果表明:①基于概率配点法的随机响应面的拟合精度很高;②弹性模量相较于内摩擦角和黏聚力对支护结构可靠指标的影响更加明显;③支护结构最大侧移的控制指标为30 mm时,三种随机变量下结构的可靠指标均大于4.5,表明基坑稳定性很好.

Based on stochastic response surface method and ABAQUS finite element software,a stochastic response surface function for the maximum lateral displacement of the diaphragm wall of the foundation pit was established,and the functional function of the diaphragm wall was obtained.The fitting accuracy of the stochastic response surface function is checked,and the reliability analysis of the diaphragm wall is performed based on the stochastic response surface method.Combined with the example of foundation pit engineering,the reliability index of the supporting structure was calculated by using stochastic response surface method.And the influence of randomness of soil parameters on the fitting accuracy of stochastic response surface and the reliability index of the structure are compared and analyzed.The results show as follows.①The fitting accuracy of the stochastic response surface based on the probabilistic collocation method is high.②Compared with the internal friction angle and cohesive force,the influence of the elastic modulus on the reliability index of the supporting structure is more obvious.③When the control index of the maximum lateral displacement of the supporting structure is 30 mm,the reliability index of the structure under the three random variables is greater than 4.5,indicating that the stability of the foundation pit is good.