双线盾构隧道下穿既有桩基桥梁变形影响分析

Analysis on Deformation Effect of Double-Line Shield Tunnel Crossing Existing Pile Foundation Bridge

本文依托城际铁路工程中典型区间,运用有限元数值分析软件,对下穿桩基桥梁的双线盾构隧道施工进行全过程模拟,并采用Peck模型进行合理计算与验证,综合分析周边地表和桥梁结构变形。研究表明:周边地表最大沉降值为1.934 mm,地表横向沉降曲线呈单峰V型正态分布;桥墩沉降最大值为2.123 mm,沿隧道方向水平位移最大值为0.220 mm,垂直隧道方向水平位移最大值为0.462 mm,桥梁结构变形以沉降为主;与距两隧道中轴线5 m处相比,距离15 m和30 m位置处桥墩竖向位移减小7.40%和14.52%,沿隧道方向水平位移减小15.90%和26.97%,垂直隧道方向水平位移减小6.07%和9.01%。

Based on the typical interval in the intercity railway project,the finite element numerical analysis software is used to simulate the whole process of the construction of the double-line shield tunnel crossing the pile foundation bridge.The Peck model is reasonably used for calculation and verification.The deformations of surrounding surface and bridge structure are comprehensively analyzed.It is shown that the maximum subsidence value of the surrounding surface is 1.934 mm,and the lateral subsidence curve of the surface shows a V-shaped normal distribution with a single peak.The maximum settlement of the bridge piers is 2.123 mm,the maximum horizontal displacement along the tunnel direction is 0.220 mm,and the maximum horizontal displacement vertical to the tunnel direction is 0.462 mm.The deformation of bridge structure is mainly settlement.Compared with the position 5 m away from the central axis of the two tunnels,the vertical displacement of the bridge piers is reduced by 7.40%and 14.52%at positions 15 m and 30 m.Under the same conditions,the horizontal displacement along the tunnel direction reduced by 15.90%and 26.97%,and the horizontal displacement vertical to the tunnel direction reduced by 6.07%and 9.01%.