粉砂地层盾构隧道开挖面稳定性离心试验及数值模拟

发布时间：2018-06-08 03:16

本文选题：粉砂 + 盾构隧道　；参考：《岩土力学》2016年11期

【摘要】：通过开展离心模型试验,对干粉砂及饱和粉砂中盾构隧道开挖面的失稳破坏特性和极限支护压力进行了研究。通过远程控制开挖面土体位移,获得了支护压力与开挖面位移间的关系曲线及开挖面达到主动极限平衡状态时的破坏模式。2组干砂离心模型试验结果表明,当隧道埋深与隧道直径比从0.5增大到1时,开挖面破坏模式从整体坍塌破坏转变为烟囱状,但极限支护压力变化较小。饱和砂土中的试验表明,开挖面水平方向破坏范围相比在相同埋深干砂中的范围扩大,极限支护压力显著增加。对开挖面破坏过程进行三维弹塑性有限元数值模拟,获得了开挖面极限支护压力和破坏机制,所得结果与试验吻合较好。进一步通过数值模拟,分析了土体强度参数、隧道埋深及渗流对极限支护压力的影响规律。结果表明,渗流条件下开挖面破坏区域及极限支护压力均大于无渗流情况,极限支护压力随内摩擦角增大而减小,随隧道埋深增大而减小。
[Abstract]:Through centrifugal model test, the unstable failure characteristics and ultimate supporting pressure of excavated surface of shield tunnel in dry silt and saturated silt are studied. By remotely controlling the soil displacement of excavated face, the relationship curve between supporting pressure and excavating surface displacement is obtained, and the centrifuge model test results of group .2 dry sand when the excavating surface reaches the active limit equilibrium state are obtained. When the ratio of buried depth to tunnel diameter increases from 0.5 to 1, the failure mode of excavated surface changes from overall collapse to chimney, but the limit support pressure changes little. The tests in saturated sand show that the horizontal damage range of excavated surface is larger than that in dry sand with the same buried depth, and the ultimate support pressure is increased significantly. Three-dimensional elastic-plastic finite element numerical simulation is carried out on the failure process of excavated face. The ultimate support pressure and failure mechanism of excavated face are obtained, and the results are in good agreement with the test results. Through numerical simulation, the influence of soil strength parameters, tunnel depth and seepage on the ultimate support pressure is analyzed. The results show that under seepage condition, the failure area of excavated face and the ultimate support pressure are higher than those without seepage, and the ultimate support pressure decreases with the increase of internal friction angle and with the increase of tunnel depth.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;
【基金】：国家自然科学基金青年科学基金(No.50908171) 上海市自然科学基金(No.13ZR1443800)~~
【分类号】：U455.43

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