盾构隧道开挖面稳定性机动分析

发布时间：2019-01-23 21:45

【摘要】：摘要：盾构在掘进的过程中,必须确保开挖面前方土体的稳定。当盾构机作用的支护压力不足时,开挖面前方的土体会向盾构机侧移动,进而导致过大的地表凹陷,土体破坏形式为主动破坏。本文基于极限分析上限定理,对盾构隧道开挖面的主动破坏形式及其支护压力进行了研究。 1.构建了盾构隧道开挖面双对数螺旋线主动破坏模式。将盾构作用在隧道开挖面上的作用力视为均布荷载,基于极限分析上限定理,推导了支护压力的上限解,编制Fortran程序求得了支护压力的最优解,分析了各参数对支护压力最优上限解及优化后破坏模式形状的影响。 2.基于空间离散技术构建的盾构隧道开挖面主动破坏模式,进一步研究土体材料的内摩擦角和粘聚力在空间上变化的开挖面稳定性问题,通过结果对比,证明了离散法的有效性,并讨论了粘聚力的各向异性、非均匀性及内摩擦角的非均匀性对支护压力最优上限解及破坏机构形状的影响。 3.依托某市的地铁工程实例,采用有限差分软件FLAC3D进行分析,并与前文的理论结果进行比较,证明了理论方法的正确性。
[Abstract]:Absrtact: in the process of shield tunneling, the stability of soil in front of excavating surface must be ensured. When the supporting pressure of shield machine is insufficient, the soil in front of excavating face moves to the side of shield machine, which leads to excessive surface depression, and the failure of soil is in the form of active destruction. Based on the upper limit theorem of limit analysis, the active failure form and supporting pressure of excavation face of shield tunnel are studied in this paper. 1. The active failure mode of double logarithmic spiral line of shield tunnel was constructed. Based on the upper limit theorem of limit analysis, the upper limit solution of support pressure is deduced, and the optimal solution of support pressure is obtained by programming Fortran program. The influence of various parameters on the optimal upper limit solution of support pressure and the shape of failure mode after optimization is analyzed. 2. Based on the active failure mode of shield tunnel excavation surface based on spatial discretization technology, the stability of excavated surface with spatial variation of internal friction angle and cohesive force of soil material is further studied, and the effectiveness of discrete method is proved by comparing the results. The effects of anisotropy, inhomogeneity of cohesive force and non-uniformity of internal friction angle on the optimal upper bound solution of support pressure and the shape of failure mechanism are discussed. 3. Based on an example of subway engineering in a certain city, the finite difference software FLAC3D is used to analyze and compare with the previous theoretical results, which proves the correctness of the theoretical method.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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