盾构隧道下穿既有铁路现场测试研究

In situ tests and study for a shield tunnel to under-pass the existing railway

文章以上海市轨道交通9号线一期工程R413线区间盾构隧道为工程背景,根据现场测试结果对盾构下穿南新环铁路干线时对周围环境的影响以及管片结构的内力变化进行了分析研究。研究结果表明,在盾构掘进过程中,盾构到达和盾尾推出这一阶段对测点沉降速率影响最大,而到后期沉降速率较小;实测的地层压力均小于初始地层应力设计值,这是由于经注浆加固后的地层有效地分担了一部分荷载所致。文中提出的盾构下穿铁路时采取的施工技术措施,可供类似工程借鉴。

Based on the shield tunneling of the first - stage project of R413 transit tunnels on line 9 of Shanghai urban rail transit, in situ tests were carried out to reveal the influence of boring on surrounding environment and the inner force variation in lining segments when the shield under - passed the south new loop railway. Results of the tests indicated, shield driving caused the maximum influence on measuring points＇ settlement rate at shield arrival and when the tail passed through, the settlement rate was decreasing at the final stage; the soil pressures measured in situ were less than the designed values of the initial pressure, because the stratum reinforced by injection could share part of load effectively. Technical measures put forward in this paper for a shield to under - pass the existing railway can be reffered to by similar projects.