顶管下穿铁路路基变形影响规律及顶进参数分析

Analysis of Influence Law and Jacking Parameters on Deformation of Railway Subgrade under Pipe Jacking

结合天津赤龙河治理工程盾构顶管下穿李港铁路,对近距双顶管长距离下穿铁路引起路基变形采用有限元数值模拟,结合监测数据和实际施工顶进参数分析,研究盾构顶管施工在顶进过程中铁路路基的时程变化及沉降槽变形规律。研究表明:顶管施工推进至距铁路路基中心线约3倍顶管管壁直径距离时,铁路路基竖向变形开始显著变化,当掘进面穿越中心线3倍顶管管壁直径距离后,铁路路基变形逐步趋于缓和并维持稳定;在掘进过程中通过调整施工参数,可以达到对穿越对象变形有效控制的目的,必要时对扰动范围内土层进行加固,可以保证铁路线路的正常安全运营,使穿越影响范围内的结构处于可控状态。

Combined with the shield pipe jacking of Tianjin Chilong river treatment project passing through LiGang railway, the detormation of subgrade caused by near distance double pipe jacking and long distance running through railway is simulated by finite element method. Combined with monitoring data and actual construction jacking parameter analysis, the time-history variation of railway subgrade and the deformation law of settlement groove during the jacking process of shield pipe jacking are studied. The results show that the vertical detormation of railway subgrade begins to change significantly when the pipe jacking construction advances to about 3 times the diameter distance of pipe jacking wall from the center line of railway subgrade. When the tunneling surface crosses 3 times the diameter distance of pipe jacking wall from the center line, the detormation of railway subgrade gradually tends to ease and maintain stability. Through adjusting the construction parameters in the tunneling process, the detormation of the crossing object can be effectively controlled. When necessary, the soil layer in the disturbed range can be reintorced, so that the normal and sate operation of the railway line can be ensured, and the structure in the affected range of the crossing can be controlled.