基坑开挖对下方既有盾构隧道影响的实测与分析

Measurement and analysis of impact of foundation pit excavation on below existed shield tunnels

对基坑开挖影响下方既有盾构隧道的机制进行了理论分析。收集了14个国内基坑工程实例,对实测数据进行了统计分析,结果表明:盾构隧道的最大竖向位移均为隆起,且有64%的隧道隆起值超过报警值(10 mm),提出了隧道最大隆起值的经验预测公式;隧道水平向位移较少量测,实测值较小;收敛变形由"水平向拉伸、竖向压缩"向"水平向压缩、竖向拉伸"转变。基于杭州市延安路某地下过街通道工程,研究了基坑开挖对下方地铁1号线盾构隧道变形的影响,对隧道竖向位移、水平向位移以及水平向收敛的实测数据进行了分析,其结果验证了理论分析和计算公式的可靠性。

The mechanism of foundation pit excavation affecting the below existing shield tunnel is researched. 14 cases of the foundation pit instance are collected to make a statistical analysis of measured data. The results show that the maximum vertical displacements of shield tunnel are all uplift, and 64% of the tunnel uplift values exceed the alarm value （10 mm）. Based on the measured statistical data, an empirical tunnel maximum uplift value prediction formula below pit is proposed. Measured data of displacements in horizontal direction are fewer surveyed; and they are also small; the convergent small deformations change from ＂horizontal stretching, vertical compression＂ to the ＂horizontal compression, vertical stretching＂. Based on the at Hangzhou Yah＇an Road, underground street passage project, the influence of foundation pit excavation on lower shield tunnel deformation in Hangzhou Metro Line 1 is researched. The measured data of ttmnel vertical displacements, horizontal displacements and horizontal convergence deformations are analyzed. The results verify the reliability of theoretical analysis and the proposed formula.