高速铁路路基下方盾构管片受力分析

发布时间：2018-08-08 19:47

【摘要】：由于高速铁路和城市轨道的迅速发展,必然会出现大量盾构隧道下穿铁路的工程实例。目前,国内外对于近距离的高速铁路与盾构隧道交叉的研究,主要集中在盾构期间隧道对于上方高速铁路的影响。对于高速铁路影响盾构隧道的研究,比较少见。因此,本文开展了高速铁路运营对下方盾构隧道管片受力的影响的研究。本文通过利用ABAQUS软件建立了盾构隧道穿越高速铁路的模型。研究了不同时速的高速列车经过不同埋深的盾构隧道正上方时候,不同拼装方式的盾构管片的动力响应。可以得出以下结论:(1)整体而言,在管片的表面,列车振动荷载引起的竖向最大加速度是随着埋深的增加而减弱的。在已有研究的基础上本文通过自己的数值进行分析和拟合,确定列车振动荷载所产生的竖向加速度是以指数函数形式在土体内衰减的。具体公式为y=2.3e^(x/1.61)其中x为节点的埋深,y为最大竖向加速度幅值。(2)对于管片内部的螺栓,列车的振动荷载的影响要先通过土体传导到盾构管片,然后振动能量将会在管片内部传导,最后到达接头螺栓部分,因为混凝土的阻尼比土体中要小,所以管片接头螺栓的竖向加速度幅值衰减的比盾构管片表面要慢。(3)管片的竖向加速度有随着列车时速增加而增加的趋势。但是车速越快,列车所产生的动应力随着埋深衰减的速率也越快,最后在埋深大于13m以后,动应力趋近于一致。(4)在列车振动荷载的作用下,管片所受到的压力随着埋深的增加迅速衰减,在管片的大部分区域,动荷载产生的等效应力不到静荷载产生的等效应力的1%,只有埋深小于6m的情况下,管片顶部区域两者的比值才达到1%。(5)盾构管片整体受到的等效应力随着列车时速的增大而增大,但是埋深比较小的部分受到的影响比较大,在350km/h的列车荷载作用下,盾构隧道顶部的动荷载产生的等效应力对静荷载产生的等效应力的比值已经接近于4%。所以,动荷载所产生的等效应力对盾构管片影响很小。
[Abstract]:Due to the rapid development of high-speed railway and urban track, there will inevitably be a large number of engineering examples of shield tunnel underpass railway. At present, the research on the intersection of high-speed railway and shield tunnel at home and abroad is mainly focused on the influence of tunnel on the upper high-speed railway during shield tunneling. It is rare to study the influence of high-speed railway on shield tunnel. Therefore, the influence of high-speed railway operation on the segment force of shield tunnel is studied in this paper. In this paper, the model of shield tunneling through high-speed railway is established by using ABAQUS software. The dynamic response of shield segments with different assembling modes is studied when high-speed train with different speeds passes directly above the shield tunnel with different buried depth. The following conclusions can be drawn: (1) on the whole, the maximum vertical acceleration caused by train vibration load decreases with the increase of buried depth on the surface of the segment. On the basis of the previous research, this paper analyzes and fits the numerical value of the train, and determines that the vertical acceleration caused by the train vibration load attenuates in the form of exponential function in the soil. The specific formula is YY 2.3e ^ (x / 1.61) where the buried depth x is the maximum vertical acceleration amplitude. (2) for the bolts inside the segment, the effect of the vibration load of the train must first be transmitted through the soil to the shield segment, and then the vibration energy will be transmitted inside the segment. Finally, the bolt part of the joint is reached, because the damping of concrete is smaller than that of soil. So the attenuation of vertical acceleration amplitude of segment joint bolt is slower than that of shield segment. (3) the vertical acceleration of segment increases with the increase of train speed. But the faster the speed is, the faster the dynamic stress of the train decays with the buried depth. Finally, when the buried depth is more than 13 m, the dynamic stress tends to be the same. (4) under the action of the vibration load of the train, The pressure on the segment decreases rapidly with the increase of the buried depth. In most regions of the segment, the equivalent stress generated by the dynamic load is less than 1 part of the equivalent stress generated by the static load, but only when the buried depth is less than 6 m. (5) the equivalent stress of the shield segment increases with the increase of the train speed, but the smaller part of the shield segment is affected greatly by the train load of 350km/h, the ratio of the two components in the top region of the segment is only 1. (5) the equivalent stress of the shield segment increases with the increase of the train speed, but the smaller part of the segment is affected greatly by the train load. The ratio of equivalent stress to static stress caused by dynamic load at the top of shield tunnel is close to 4. Therefore, the equivalent stress produced by the dynamic load has little effect on the shield segment.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U455.43

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