考虑约束条件下的基坑围护结构弯矩估算方法研究

Research on estimation method of bending moment of foundation pit retaining structure considering constraints

基坑围护结构的变形与弯矩是评价基坑安全状态的重要指标,但从目前工程现状看,合理全面的获得围护结构的弯矩具有一定的难度。为此在分析基坑围护结构常见的边界约束条件的基础上,引入拉格朗日乘数因子,结合材料力学理论及最小二乘法数学原理,建立了一种可考虑基坑围护结构约束条件的弯矩简便估算方法,同时,采用了工程实例对该方法进行了验证分析。结果表明:在准确获得基坑围护结构深层水平位移和真值约束条件的前提下,相比普通的多项式拟合方法,该方法得到的弯矩分布曲线与实测结果接近,弯矩分布规律更符合实际情况,具有良好的适用性,可为类似基坑工程的围护结构弯矩估算提供参考。

The deformation and bending moment of the retaining structure of the foundation pit are important indicators for evaluating the safety status of the foundation pit.However,judging from the current engineering status,it is difficult to obtain the bending moment of the retaining structure reasonably and comprehensively.Therefore,based on the analysis of the common boundary constraints of the foundation pit retaining structure,this paper introduces the Lagrangian multiplier factor,and combines the theory of material mechanics and the mathematical principle of the least square method to establish a consideration of the foundation pit retaining structure A simple method for estimating the bending moment of the constraint conditions,and at the same time,an engineering example is used to verify and analyze the method.The results show that under the premise of accurately obtaining the deep horizontal displacement and true value constraint conditions of the foundation pit retaining structure,compared with the ordinary polynomial fitting method,the bending moment distribution curve obtained by this method is close to the measured result,and the bending moment distribution law is more It conforms to the actual situation and has good applicability.It can provide a reference for the estimation of the bending moment of the enclosure structure of similar foundation pit engineering.