盾构隧道近距离侧穿桩基的施工力学响应研究

Construction Mechanical Response of a Shield Tunnel Adjacent to Existing Pile Foundation

盾构开挖近距离侧穿既有桩基的问题值得关注。采用两阶段位移法,提出了近距离盾构开挖对侧向桩基影响的简化计算方法。以典型工程实例为背景,计算桩基受影响规律,且与三维数值计算结果对比分析。结果表明:盾构开挖引起侧向桩基最大水平位移为4.25 mm,相应弯矩和剪力最大值分别为1 176.09 k N·m、505.1 k N。桩受盾构开挖影响范围可以通过45°+φ/2的角度扩散计算确定。与数值计算结果对比分析表明,文章提出的计算方法可行,可用于预测盾构开挖引起紧邻既有桩基的扰动。

More attention has focused on the issue of shield tunneling across existing pile foundation. The two-stage approach was conducted to propose the simplified calculation method of impact on adjacent existing pile foundation by shield tunneling in close range. The influencing law of existing pile was calculated based on a typical engineering example, as well as the result was analyzed and compared with the result which was calculated by three-dimensional numerical simulation. The results show that the maximum horizontal displacement of adjacent existing pile foundation caused by shield tunneling is 4. 25mm, and the corresponding bending moments, the shear forces are 1176. 09 kN＂ m and 505. lkN respectively. The influencing scope of existing pile foundation caused by shield tunneling can be determined by 45 o ＋ ~p/2 angular spread. Through the comparison with numerical calculation results, it is indicated that the method proposed in this work is feasible and it can be used to predict the perturbation of existing pile caused by adjacent shield construction.