软土饱水地层深大基坑对浅埋地铁区间隧道的影响及变形控制研究

Study on Influence and Deformation Control of Deep and Large Foundation Pits in Soft Soil Water-saturated Stratum on Shallow Buried Subway Tunnels

随着社会经济的发展,软土饱水地层深大基坑对浅埋地铁区间隧道的影响越来越突出。该文以无锡首例近接隧道20m深大基坑工程施工为例,介绍了基坑开挖施工期间对相邻运营浅埋隧道的影响及所采取的变形控制措施。实践表明,通过在设计阶段控制支护体系刚度、施工期间利用时空效应优化开挖方案,做到分区分块、加强基坑监测并做好应急预案,开挖到底后隧道变形是可控的。同时应高度重视近接隧道地连墙施工对隧道的影响,必要时可采用槽壁加固等措施减少地层扰动,所取得的经验可为同类工程提供参考。

With the development of social economy,the influence of deep and large foundation pits in soft soil and water-saturated strata on shallow buried subway interval tunnel has become more and more prominent.Taking the first construction case of the first 20m deep and large foundation pit close to the tunnel in Wuxi as an example,this paper introduces the influence of foundation pit excavation on adjacent operation of shallow buried tunnels and the deformation control measures taken during the excavation of foundation pit.Practice shows that after excavation to the bottom,the tunnel deformation is controllable by controlling the stiffness of the support system at the design stage,optimizing the excavation scheme by using the space-time effect to achieve zoning and blocking during the construction period and strengthening foundation pit monitoring and making emergency plans.At the same time,great attention should be paid to the impact of the construction of the ground connecting wall of the adjacent tunnel to the tunnel.If necessary,measures such as groove wall reinforcement can be adopted to reduce the stratum disturbance.The valuable experience obtained can be a useful reference for similar projects.