高速列车动荷载作用下盾构管片疲劳破坏形式及寿命预测研究

发布时间：2018-06-30 19:44

本文选题：盾构隧道 + 错缝拼装　；参考：《西南交通大学》2017年硕士论文

【摘要】：针对目前盾构隧道下穿既有铁路工程越来越多,高铁车致动载对下穿盾构结构的影响日益凸显。本文运用数值模拟的动力计算方法,旨在研究车致动载对下方盾构管片的动力影响,主要内容如下:1)采用错缝拼装管片的精细化模型做动力计算,为较好地模拟无限岩土体,建立有限元—无限元耦合计算模型,基于无限元单元的定义规则,采用MATLAB程序化批量处理修改无限元单元,极大地提高了计算效率。2)分析得出下穿盾构区间的动应力响应规律,明确了结构受车致动载的危险部位。与均质圆环模型对比分析,得出管片错缝拼装的计算模型可以更好地模拟实际工程中螺栓的受力与错缝拼装对管片的作用。3)研究了车致动载对下穿盾构地层的衰减规律,通过非线性拟合得出应力沿地层深度变化曲线公式。与目前常用的拟静力法作对比分析,可以看出相比于动力计算法有30%至45%的安全储备,是一种偏保守的通用设计方法。4)建立不同埋深工况的错缝拼装模型,分析了不同工况下各分析点管片与螺栓的应力响应规律。管片所受总应力由隧道初始应力与车致荷载动应力共同影响,由于二者分别随着埋深增加而增大和减小,因此随着埋深的变化,二者对各分析点影响的比重不同,总的应力变化趋势也有所不同。5)比较分析了两种MJS加固方式的应力变化规律,得出MJS加固方式对模拟施工开挖的初始应力影响远远大于车致荷载对管片的动应力影响。6)基于车致荷载下各工况的应力水平,通过结构疲劳寿命预测公式,得到各工况下的疲劳寿命,总结得出了不同埋深下管片疲劳寿命的影响规律。
[Abstract]:At present, there are more and more existing railway projects under the shield tunnel, and the influence of the moving load of the high-speed train on the structure of the shield tunneling is becoming more and more prominent. In this paper, the dynamic calculation method of numerical simulation is used to study the dynamic effect of vehicle driving load on the bottom shield segment. The main contents are as follows: 1) dynamic calculation is done by using the refined model of staggered joint assembly segment, in order to simulate the infinite rock and soil better. Based on the definition rules of infinite element, the finite element coupling model is established, and the infinite element is modified by MATLAB program batch processing. The calculation efficiency is greatly improved by .2) the law of dynamic stress response in the interval of shield tunneling is obtained by the analysis of the finite element and infinite element coupling model, which is based on the definition rule of infinite element. The dangerous part of the structure subjected to the moving load of the vehicle is identified. Compared with the homogeneous ring model, it is concluded that the calculation model of segment disjoint assembly can better simulate the force of bolt and the action of staggered joint assembly on segment in practical engineering. 3) the attenuation law of vehicle driving load on underpass shield formation is studied. The formula of stress variation curve along formation depth is obtained by nonlinear fitting. Comparing with the pseudostatic method, it can be seen that there is a 30% to 45% safety reserve compared with the dynamic calculation method, and it is a conservative general design method .4) to establish the fault joint assembly model with different buried depth working conditions. The stress response of segments and bolts at different analysis points under different working conditions is analyzed. The total stress of the segment is influenced by both the initial stress of tunnel and the dynamic stress of vehicle-induced load. Because they increase and decrease with the increase of burying depth, the proportion of influence of them on each analysis point is different with the change of buried depth. The trend of total stress change is different from that of 5. 5) the stress variation law of two kinds of MJS reinforcement methods is compared and analyzed. It is concluded that the effect of MJS reinforcement on the initial stress of simulated construction excavation is much greater than that on segment dynamic stress by vehicle-induced load (.6). Based on the stress level of each working condition under vehicle-induced load, the fatigue life prediction formula of structure is obtained. The fatigue life under different working conditions is obtained, and the influence of different buried depth on fatigue life of pipe is summarized.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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