新建双线盾构隧道下穿既有隧道变形规律及控制技术研究

Stduy on Deformation Law and Control Technology of Newly Built Double Line Shield Tunnels Undercrossing Existing Tunnels

针对下穿工程的既有盾构隧道安全风险问题,依托苏州地铁3号线金鸡湖西站—东方之门站区间下穿1号线运营隧道工程,采用数值方法模拟新建双线盾构隧道下穿既有盾构隧道施工过程,分析新建盾构隧道引起地表沉降槽与纵向沉降、既有盾构隧道变形、新建盾构隧道拱顶沉降与水平收敛特性,得到以下主要结论:①既有隧道的存在,既会减少新建隧道开挖引起的地表沉降,也会减少新建隧道开挖引起的地表沉降纵向范围;②新建隧道引起地表沉降槽最大值位于新建双线隧道中心线上方;③既有隧道变形主要集中在新建隧道上方,呈对称分布。确定了施工掘进参数,形成了运营隧道保护,补偿注浆、盾体径向注浆、二次注浆和微扰动全断面注浆等既有隧道变形控制施工技术,有效保证了施工的顺利进行。

In view of the safety risk of the existing shield tunnel in the underpass project,based on the project of the section tunnel between Jinjihuxi Station and Dongfangzhimen Station of Suzhou Metro Line 3 passing underneath Line 1 operating tunnel,this paper adopts the numerical simulation to analyze the construction process of the newly built double line shield tunnels undercrossing the existing shield tunnels.The analysis focuses on various aspects including the surface settlement trough and longitudinal settlement caused by the new shield tunnels,the deformation of the existing shield tunnels,the vault settlement and horizontal convergence characteristics of the new shield tunnels.Based on the research,the key conclusions are drawn:①The presence of existing tunnels not only reduces the surface settlement resulting from the excavation of new tunnels,but also limits the longitudinal range.②The maximum value of surface settlement trough caused by the new tunnel occurs above the center line.③The deformation in the existing tunnel mainly concentrates at the top section with symmetrical distribution.The construction tunneling parameters are determined,and the existing tunnel deformation control construction technologies,such as operation tunnel protection,compensation grouting,shield radial grouting,secondary grouting and micro disturbance full section grouting are formed,which effectively ensure the smooth construction progress.