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以不同埋深双隧道、不同开挖顺序对临近地埋管线的影响为研究目的,在离心模型试验中同时考虑隧道开挖所致地层损失效应和质量损失效应,并采用考虑土体非线性小应变特性的HP(Hypoplasticity亚塑性)模型和基于地层损失比的位移控制法进行有限元模拟分析。研究结果表明,不同埋深双隧道、不同开挖顺序对地表沉降、管线沉降及管线弯曲应变的影响较大。双隧道开挖完成后管线下凸区(管线底部受拉区)分布范围为-2.5D_T~1.5D_T(DT为隧道外径),且管线下凸区最大弯曲应变约为管线上凸区(管线底部受压区)最大弯曲应变的2倍。不应简单采用叠加原理对不同埋深先后开挖双隧道所致地表沉降、管线沉降及管线弯曲应变进行预测,应合理考虑后继隧道开挖所致土体的累积剪切应变及管-土相对刚度对预测结果的影响。
In order to study the influence of double tunnel with different depth and different excavation sequence on adjacent buried pipeline, considering the effect of tunnel excavation on formation loss and mass loss in the centrifugal model test, (Hypoplasticity) plasticity model with strain characteristics and displacement control method based on formation loss ratio. The results show that different tunnels with different depths have different influences on surface settlement, pipeline settlement and pipeline bending strain. After double-tunnel excavation is completed, the pipe under the embankment (pipeline at the bottom of the tension zone) distribution range of -2.5D_T ~ 1.5D_T (DT is the tunnel outer diameter), and the pipe under the convex zone maximum bending strain of the pipeline on the convex area Bottom compression zone) maximum bending strain of 2 times. We should not simply use the principle of superposition to predict the ground settlement, pipeline settlement and pipe bending strain induced by double tunnels with different depths. The cumulative shear strain of soil due to subsequent tunnel excavation should be considered reasonably. Effect of Stiffness on Prediction Results.