港渠开挖卸载对既有下卧地铁盾构隧道影响分析

Analysis on Influence of Port Channel Excavation Unloading on Existing Underground Metro Shield Tunnel

通过对位于既有下卧盾构隧道的港渠渠底开挖卸载工程案例介绍,采用卸荷比和基坑卸荷影响深度分析方法,定性判断渠道卸载影响深度,同时对卸荷后所产生的隧道抗浮稳定性进行了验算,并采用大型岩土与隧道有限元分析Midas/GTS对卸荷所引起的隆起变形进行了数值计算。依据多项分析结果,推荐采取土体加固处理、渠道底部硬化、分层分段卸载,以及信息化监测的措施。并且,其措施的有效性也在工程实施中得到了验证。

According to the introduction on the excavation unloading engineering case at the bed of port channel of the existing underground shield tunnel, the unloading ratio and foundation pit unloading influence advanced analysis method is used to qualitatively judge the channel unloading influence depth, and to check up the tunnel anti-floating stability after unloading. The large geotechnical and tunnel finite element analysis Midas/GTS is sued to numerically calculate the upheaval and deformation caused by unloading. Based on many analysis results, it is to recommend the methods of soil reinforcing treatment, tunnel bed hardening,unloading by layers and sections, and the informationized monitoring measures. The effectiveness of measures is verified in the engineering implementation.