地铁区间隧道下穿福厦铁路风险分析

Risk Analysis of Metro Section Tunnel under Fuzhou-Xiamen Railway

厦门地铁4号线厦门北站至同安食品工业园区间隧道下穿福厦铁路,地铁盾构隧道施工期间必须确保铁路正常运行,这对地铁设计与施工提出较高要求。对区间隧道下穿福厦铁路路基重大风险源的施工过程进行三维有限元分析,通过采取相应的工程措施确保福厦铁路行车安全。分析结果表明:通过采用土压平衡式盾构施工并严格控制施工参数,对一定范围内的土体进行改良、采取D24型钢便梁加固轨道等措施,可以有效地控制福厦铁路路基沉降;铁路路基沉降槽随区间隧道的开挖而发生动态变化,左线开挖时呈三次抛物线,再开挖右线时呈二次抛物线;采取措施后的工程风险等级可降为Ⅲ级。

Fuzhou-Xiamen Railway as a dedicated passenger line is an important part of Hangzhou-Shenzhen Railway,and it poses high requirements to the construction of the section tunnel to allow non-stop and non-speed-limit operation of the railway. With reference to Xiamen North Railway Station to Tong ＇ an Food Industrial Park section tunnel of Xiamen Metro Line 4,this paper conducts threedimensional finite element analysis of major risksources in the preliminary design to ensure the safety of Fuzhou-Xiamen Railway with engineering measures. The results of analysis indicate that the settlement of Fuzhou-Xiamen Railway can be effectively controlled to ensure the safety during the period of construction by such measures as the use of the earth pressure balanced shield,strict control of the construction parameters,soil conditioning of a certain area,and reinforcement of railway track with steel beam of D24. The settlement of ground surface along the Fuzhou-Xiamen Railway is subject to dynamic change during the excavation of the running tunnel,the left line presents a cubic parabola and the right line shows a second degree parabola.Engineering risk level is reduced to Ⅲ level because of certain measures.