【作者】 陈建明；

【导师】 程谦恭；

【作者基本信息】 西南交通大学 ， 地质工程， 2013， 硕士

【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。合福高铁官山底特大桥下方采空区主要是采空巷道,本文依托该项目,以模型试验为手段,研究高速铁路采空区上方桥基变形规律,具体研究内容和成果如下：(1)桥梁桩基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体,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一定值。(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,但当荷载增加至1850N时,桩间土应力增加幅度减小,桩顶应力增加幅度变大；桩土荷载分担比随荷载增加而增大,但其增加幅度逐渐减小。(4)承台和桩间土沉降量都随荷载的增加而增大；两桩中心土体沉降量要稍大于四桩中心土体的沉降量；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大于非采空区处土体沉降量；位于采空巷道上方的承台部分沉降量大于其它部分沉降量。更多还原

【Abstract】 In recent years, with the continuous construction of high-speed railway, many railway lines cross coalmines and the goaf. The presence of goaf roadway is bound to have a certain impact on the deformation of the bridge foundation of high-speed railway. Therefore, it is necessary to research the deformation of high-speed railway bridge foundation overlying the goaf roadway.In this dissertation, based on the GuanShanDi bridge of Hefei-Fuzhou high-speed railway, the deformation regularity of the bridge foundation above the mined-out area of high-speed railway is studied by model test The specific contents and the achievements of the research are as follows:(1) The pile’s axial force of the bridge gradually decreases from the top of the pile to the bottom. At the same section of the piles, the axial force of the piles enlarges with the increment of load. The axial force on the top of the pile which is in the center of the cap is maximum; The axial force of the piles which go through the goaf roadway is a certain value in the roadway.(2)The skin friction of piles is first increment and then turns to decrease. At the same section of the piles,it enlarges with the increment of load; the skin friction of piles which go through the goaf roadway is zero.(3)At the beginning of loading, stresses of both soil among piles and pile top will increase rapidly for a while. But when the load increases to1850N, the increase of stress of soil among piles is reduced and the increase of stress of pile top is enlarged. The sharing ratio of the pile-soil load increases with the increment of load, but the extent of increasing gradually gets small.(4) The settlement of the cap and the soil among piles increases with the increment of load. The central soil settlement of two piles is slightly larger than that of four piles. The settlement at the roof of the goaf roadway increases as the increment of load. The soil settlement above the goaf roadway is greater than that of other places. The settlement of parts of the cap located on the goaf roadway is greater than that of other parts of the cap.更多还原