新建地铁暗挖隧道下穿既有地铁与高铁线路变形规律研究

Study on Deformation of New Underground Tunnel Passing Existing Subway and High-speed Railway

为研究新建暗挖隧道下穿既有地铁与高铁路基过程中引起的钢轨与地表变形规律,依托北京地铁27号线暗挖隧道下穿地铁13号线与京张高铁工程,采用数值模拟的方法对施工过程进行动态模拟,分析开挖施工完成后钢轨竖向位移的变化规律,以及在施工过程中钢轨不平顺和地表沉降规律。研究表明,钢轨竖向位移最大值出现位置与隧道和既有线的相对位置有关,越靠近开挖区域变形越大,最大值为-5.23 mm;所有钢轨的不平顺均出现2次先增加后减小的过程,显示为2个波峰,但波峰出现的位置不同;地表沉降槽中心随施工步逐渐移动,当开挖位置远离监测断面后,地表沉降增长缓慢,说明初期支护可以保证隧道结构的稳定。

In order to study laws of rail and surface deformation during the new underground tunnel crossing the existing subway and high-speed railway subgrade,based on the underground tunnel of Beijing Metro Line 27 crossing Subway Line 13 and Beijing Zhangjiakou High-speed Railway,the construction process was dynamically simulated by numerical simulation method,and the law of vertical displacement of rail after excavation was analyzed.The distribution law of rail irregularity and surface settlement during construction was discussed in the meantime.The results show that,the position where the maximum vertical displacement of rail appears is related to the relative position of tunnel and existing line.The closer it is to the excavation area,the greater the deformation is,and the maximum value is-5.23 mm;The irregularity of all rails increases first and then decreases twice,showing two peaks with different location;At the same time,the center of the settlement tank on the surface gradually moves to the center with the construction steps.With the excavation area away from the monitoring area,the displacement of the subgrade surface increases slowly,which indicates that the tunnel structure is stable.