地铁车站密贴下穿既有线施工技术

Construction Techniques of Subway Station Closely Crossing Underneath the Existing Tunnel

随着城市轨道交通网络的密集化,地铁车站施工将越来越多地面临密贴下穿既有线的难题.密贴下穿既有线施工危险性较大、施工工艺复杂.以北方某地铁车站密贴下穿既有轻轨线施工为背景,分析下穿施工技术难点,研究六导洞法暗挖、深孔注浆加固、顶升沉降控制、沉降监测等技术,形成了下穿既有轻轨结构施工的成套技术和施工指南.沉降及形变检测结果表明,主动顶升措施对既有线隧道变形缝开合度和底板沉降量的控制效果显著,能有效保证车站下穿既有线施工的安全性、经济性和高效性.

With the densification of urban rail transit network,subway stations will face more and more problems of closelycrossing underneath existing tunnels.The construction of closely crossing underneath the existing tunnel has the characteristicsof high risk and complex technology.Based on the construction of a subway station in the north of China,technical difficultiesof underpass construction were analyzed,the technology of six heading method for concealed excavation,deep hole groutingreinforcement,jacking settlement control,settlement monitoring and so on were studied,and a set of technology andconstruction guide for closely crossing underneath the existing tunnel were formed.Results of settlement and deformationdetection show that active jacking measures have significant effects on the control of deformation at joints and settlement forexisting line tunnels,and can effectively ensure the safety,economy and efficiency of the station construction when it crossesunderneath the existing line.