盾构隧道下穿引起铁路轨道沉降变形数值研究

Numerical study on settlement and deformation of railway tracks induced by shield tunnelling crossing under railway track

结合福州某地铁双线盾构隧道下穿铁路轨道的工程实例,采用有限元数值模拟与实测值相结合的方法,分析研究了盾构隧道在下穿的施工过程中对轨道沉降、轨道水平偏差以及轨向偏差影响的一般性规律,探讨了不同盾构隧道埋深条件下的轨道沉降与变形规律。研究表明,轨道沉降主要发生在盾构掌子面到达前、盾构通过期间及盾尾通过后的3个阶段;最大水平偏差一般出现在掌子面到达隧轨相交处位置;最大轨向偏差一般发生在掌子面到达轨道线路之前或通过轨道线路以后1倍的盾构隧道直径左右的距离位置;同时表明,在不考虑地下水位的情况下,盾构隧道埋深越大,轨道线路沉降与变形越小,列车运行越平稳安全。

Combined with an engineering example of a double line shield tunnel crossing underneath railway track in Fuzhou,finite element numerical simulation and measurement data were utilized to analyse the regularity of the influences of shield tunnel crossing underneath railway track on the track settlement,the track horizontal deviation and the track direction deviation. The track settlement and deformation under the condition of different tunnel depths were discussed. The track settlement occurs mainly at three stages： before the arrival of the shield tunnel face,during the passing period of the shield,and after the pass of the shield tail. The maximum horizontal deviation usually occurs at the time when the tunnel face arrives at the intersection position of the shield tunnel and the railway track. The maximum track direction deviation usually occurs before tunnel face arrives at the track or approximately 1 times of the diameter of the shield tunnel after shield tunnel face passes the track. At the same time,when the underground water level is not considered,the greater the depth of the shield tunnel and the smaller the settlement and the deformation of the track line,the more stable the train operates.