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通过离心模型试验模拟平行盾构隧道近接开挖施工,研究了盾构隧道近接开挖对既有隧道结构内力、管片变形和地表沉降的变化规律。结果表明:1隧道开挖引起地表沉降的大小与开挖的步骤有关,而沉降槽的范围基本不变;2既有隧道靠近新建隧道一侧受拉,这一侧弯矩出现负增量,侧向土压力也有一定的减小,且既有隧道直径水平向变大,而垂向直径基本不受影响;3由于土拱效应,新建隧道已完成开挖部分管片拱顶的土压力随开挖进程先减小后增大;4采用地层结构法可以准确模拟隧道开挖过程的隧道结构力学特性与变形规律。
Centrifuge model test is used to simulate the construction of the parallel shield tunnel near the excavation, and the variation regularity of the internal forces, the deformation of the segment and the settlement of the surface of the existing tunnel are studied. The results show that: 1 The size of surface subsidence caused by tunnel excavation is related to the excavation steps, while the scope of the sedimentation tank is basically unchanged; 2 The existing tunnel is pulled near the new tunnel, The lateral earth pressure also decreases to a certain extent, and the diameter of existing tunnels increases horizontally while the vertical diameter is basically unaffected. 3 Due to the effect of soil arching, the earth pressure of the newly built tunnel has been completed The excavation process firstly decreases and then increases. (4) The stratum structure method can accurately simulate the tunnel structure mechanical characteristics and deformation rules during tunneling.