全断面基坑开挖过程中位移反演及稳定性分析

Displacement Back Analysis and Stability Analysis of Full Section Foundation Pit during Its Excavation

分析断面非对称的复杂基坑时,常规半断面分析法的计算精度容易受边界效应的影响;本文探讨了一种以基坑整个断面为分析对象的全断面分析法,并模拟复杂基坑的开挖过程。在基坑开挖过程中,利用已测得的变形监测数据,反演分析得出与实际工况相吻合的土层等效弹性模量,将反演所得参数代入FLAC,计算出相应工况下基坑的变形和安全系数,并对下一工况的变形进行预测。实例分析结果表明,对于类似断面非对称的复杂基坑,全断面法的计算结果相对半断面法更加接近实测结果,能较好地指导施工,并对基坑开挖的安全性进行评价。

For the non-symmetrical complex foundation pit, the calculation precision of half section analysis method is easy to be affected by boundary effect; this paper discussed a full section analysis method based on the full section of foundation pit, and simulated the excavation process of complex foundation pit. During the excavation, the equivalent elastic modulus of soil layers consistent with actual conditions can be calculated through back analysis based on the measured deformation monitoring data, after substituting the equivalent elastic modulus into FLAC, the deformation and safety factor of foundation pit in corresponding case can be calculated, and the deformation in next case also can be predicted according to the calculated equivalent elastic modulus. According to the results of engi- neering example, for analyzing the non-symmetrical complex foundation pit, compared with half section analysis method, the calculated results of full section analysis method were more close to the measured data, which can guide the construction well and evaluate the safety of foundation pit excavation.