圆形盾构隧道开挖引起的黏土长期沉降理论解

Theoretical Solutions for Shield Tunneling induced Long term Settlements in Clays

摘要:

基于Sagaseta源汇理论和Park位移边界条件，对排水条件下圆柱孔收缩问题的位移场进行半无限空间及隧道断面的椭圆变形模式修正，得到圆形盾构隧道开挖引起的土体长期沉降理论解.引用离心机试验以及位移控制模式(DCM)有限元模拟和工程实例对理论解进行对比验证.分析结果表明，对于地表长期沉降的预测，除了采用边界条件1(未修正)的理论解计算结果与试验结果偏差较大，其余三种边界条件计算结果与试验和有限元结果吻合较好，为保守建议采用边界条件2进行计算；理论解总体与实测较为一致.

Abstract:

Theoretical solutions for tunneling induced long term ground settlements in clays are presented by modifying displacement solutions of drained contraction of cavity based on the Sagaseta’s image technique and the Park’s displacement boundary condition. The proposed solutions are compared with quoted centrifuge tests， finite element simulation based on displacement controlled model (DCM) and field studies. The results indicate that for the prediction of long term surface settlements， the theoretical solutions under uncorrected boundary condition 1 deviate significantly from the centrifuge tests， while those under the remaining three boundary conditions are in good agreement with the centrifuge tests and finite element method， and boundary condition 2 is recommended as a conservative approach. Generally agreement of the predicted surface settlements can be seen with field observations.