双线盾构隧道施工对近接桥梁桩基的影响研究

以山西太原地铁2号线双线盾构隧道近距离穿越高架桥桩基为研究对象，建立三维有限元模型，考虑土仓压力、盾壳与土层的摩擦力、注浆压力的影响，模拟盾构隧道开挖掘进过程，分析桩基变形规律。结果表明:双线盾构隧道开挖完后，近接桩基承台发生的竖向位移为-3.21 mm；桩基竖向位移和垂直隧道开挖方向的水平位移，主要发生在隧道开挖距桩前10 m和桩后10 m之间，沿隧道开挖方向的水平位移，主要发生在隧道开挖至距桩前20 m和桩后20 m之间；垂直隧道开挖方向的水平位移和沿隧道开挖方向的水平位移最大值均出现在隧道掘进通过桩基过程中，分别达9.47 mm和-11.92 mm，均出现在隧道中心高度处；在隧道掘进过程中需采取桩基保护措施。

Study on Influence of Double-line Shield Tunnel Construction on Neighboring Bridge Pile Foundation

In relation to the double-line shield tunnel of Taiyuan Metro Line 2 in Shanxi Province passing through the neighboring pile foundation of viaduct, a three-dimensional finite element model was built, with the soil warehouses pressure, the friction between shield shell and soil layer and the grouting pressure taken into consideration, to simulate the tunneling process and to analyze the deformation law of pile foundation. The result shows that, after the double-line shield tunnel has been excavated, the vertical displacement of the adjacent pile cap is -3.21 mm; the vertical displacement of piles and the horizontal displacement perpendicular to the direction of tunneling mainly occur within the scope where the tunnel is excavated 10m before and 10 m behind the piles, and the horizontal displacement along with the direction of tunneling mainly occur within the scope where the tunnel is excavated 20 m before and 20 m behind the piles; the maximum horizontal displacement of the piles perpendicular to and along with the direction of tunneling occur in the process when the tunneling passes through the pile foundation, reaching 9.47 mm and -11.92 mm at the central height of the tunnel, respectively; therefore, neighboring pile foundation should be protected in tunneling.