高速铁路采空区桥基变形监测分析

发布时间：2018-03-07 07:00

本文选题：现场监测　切入点：桥基　出处：《西南交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来,随着铁路的不断建设,很多铁路项目都穿越煤矿及其采空区。而高铁建设要求极为严格,对于不可避免要穿过小型采空区或采空巷道的高铁而言,它们的存在会导致桥基发生不均匀沉降,进而影响列车运营的安全性,严重时甚至会造成列车脱轨。因此,有必要对采空巷道上方的高铁桥基变形进行分析研究。本文基于合福铁路上饶段官山底特大桥59号墩台(DK499+584.180)和62号墩台(DK499+682.28),以现场监测为手段,研究高速铁路采空区上方桥基的变形规律和荷载传递规律；同时,基于实测桥基的沉降变形曲线,以指数曲线法对桥基承台的沉降变形曲线进行回归分析和预测评估,探讨群桩加固措施对采空区稳定性的作用效果。所获得的结论如下： (1)桥梁桩基桩身的轴力由桩顶到桩底逐渐减小；在同一截面处桩身轴力随荷载的增加而增大；位于承台中心处的桩,其桩顶轴力最大；穿过采空巷道的桩,在巷道内的桩身轴力为固定值。 (2)桩的侧摩阻力沿桩长呈现先增大后减小的变化规律；在同一截面处桩的侧摩阻力随荷载的增加而增大；穿过采空巷道的桩,在巷道内的桩身侧摩阻力为零。 (3)加载初期,桩间土应力与桩顶应力都存在一个迅速增大的过程,但随着荷载的逐渐加大,桩间土应力增加幅度减小,桩顶应力增加幅度变大；侧摩阻力分担比、桩荷载分担比和桩土应力比随着荷载增加而增大。 (4)承台和地层的沉降量都随荷载的增加而增大；采空巷道顶板处沉降随着荷载的增加而增大；采空巷道上方土体沉降量略大于非采空区处土体沉降量；位于采空区上方的承台部分沉降量大于其它部分的沉降量。 (5)采用群桩加固措施后,桥基的工后沉降量和最终沉降量均满足规范和设计要求,说明此种加固措施对增强采空区稳定性行之有效。
[Abstract]:In recent years, with the continuous construction of railways, many railway projects have passed through coal mines and their goaf. Their existence will lead to uneven settlement of the bridge foundation, which will affect the safety of the train operation, and even cause train derailment, so it is necessary to analyze and study the deformation of the high-speed railway bridge foundation above the roadway. Based on DK499 584.180) and DK499 682.28, the deformation law and load transfer law of bridge foundation above goaf area of high speed railway are studied in this paper, based on DK499 584.180) and DK499 682.28, respectively. Based on the measured settlement and deformation curve of bridge foundation, the regression analysis and prediction of settlement and deformation curve of bridge abutment are carried out by exponential curve method, and the effect of pile group reinforcement on the stability of goaf is discussed. The conclusions are as follows:. 1) the axial force of pile body of bridge pile foundation gradually decreases from pile top to pile bottom; at the same section, the axial force of pile body increases with the increase of load; at the center of pile cap, the axial force of pile top is the largest; The axial force of the pile in the tunnel is a fixed value. (2) the lateral friction of the pile increases first and then decreases along the pile length; the lateral friction increases with the increase of load at the same section; the pile passing through the mined-out roadway has zero lateral friction in the roadway. 3) at the beginning of loading, there is a rapid increase process of soil stress between piles and stress at the top of pile, but with the increasing of load, the increase of soil stress between piles decreases, the stress of pile top becomes larger, the ratio of lateral friction to friction increases. The pile load sharing ratio and pile soil stress ratio increase with the increase of load. 4) the settlement of cap and stratum increases with the increase of load, the settlement of roof increases with the increase of load, the settlement of soil above the roadway is a little larger than that of soil in non-goaf. The settlement of the cap located above the goaf is greater than that of the other parts. 5) after adopting pile group reinforcement measures, both the post-construction settlement and the final settlement of the bridge foundation meet the specifications and design requirements, which shows that the reinforcement measures are effective in enhancing the stability of goaf.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.13;U443.1;U446

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