超载作用下含砂砾石成层边坡破坏机理及稳定性的研究

发布时间：2018-03-06 22:25

本文选题：含砂砾石成层边坡　切入点：变形破坏机理　出处：《湖南科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着我国经济建设的高速发展,城市高层建筑越来越多,基坑开挖也朝深大方向发展,基坑开挖过程中,成层土夹层状砂砾石的情况较常见,设计时常将其视为均质边坡进行稳定性分析,计算结果与实际差别较大。因此,对超载作用下含砂砾石成层边坡破坏机理及稳定性进行研究具有一定的现实意义。在熟悉边坡稳定性理论及方法的基础上,通过设计室内模型试验、数值模拟、理论分析相结合的方法对超载作用下含砂砾石成层边坡的变形破坏机理、工作性状及稳定性进行研究。相关研究成果如下:1、通过室内模型试验得出含砂砾石成层边坡在坡顶超载作用下的位移变化规律,对照各类工况发现含砂砾石成层边坡在失稳破坏时均为局部剪切破坏,滑动面为圆弧+直线型。2、采用FLAC对室内试验各工况进行数值模拟,结果表明各类工况下的模型破坏机理与室内模型试验吻合,滑动面为圆弧+直线型。并通过多种工况计算,分析了超载作用下含砂砾石成层边坡的极限承载能力和位移随不同砂砾石层厚度、不同砂砾石层位置、不同坡比、加载面积的差异等因素下的变化规律。对承载力影响较大的因素有:砂砾石层厚度、砂砾石层位置,坡比。3、建立超载作用下含砂砾石成层边坡的滑动面模式的运动容许速度场,采用极限分析上限法求出了其极限承载力的计算公式,并将其与室内试验结果和数值模拟结果进行相互对比,得出上限法在求解超载作用下含砂砾石成层边坡的极限承载力时与室内试验的差值在10.42%左右,具有一定的工程实用价值。
[Abstract]:With the rapid development of economic construction in our country, more and more high-rise buildings are built in cities, and the excavation of foundation pit also develops in the direction of deep. During the excavation of foundation pit, the situation of layered soil intercalated sand and gravel is more common. The design often regards it as a homogeneous slope for stability analysis, and the result of calculation is quite different from that of practice. It is of practical significance to study the failure mechanism and stability of the slope with sand and gravel layers under overload. On the basis of familiar with the theory and method of slope stability, the numerical simulation is carried out through the model test in the design room. The mechanism of deformation and failure of sandy gravel stratified slope under the action of overload is analyzed by the method of theoretical analysis. The related research results are as follows: 1. Through the indoor model test, the displacement variation law of the slope with sand and gravel layers under the action of overloading on the top of the slope is obtained. Compared with all kinds of working conditions, it is found that the slope with sand and gravel layers is local shear failure when it is unstable, and the sliding surface is circular arc linear type. FLAC is used to simulate each working condition of indoor test. The results show that the failure mechanism of the model under various working conditions is consistent with that of the indoor model test, and the sliding surface is a circular arc straight line. The ultimate bearing capacity and displacement of the gravel-bearing slope under the action of overload are analyzed with different thickness of gravel layer, different location of gravel layer and different slope ratio. The influence factors on the bearing capacity are: the thickness of gravel layer, the location of gravel layer, the slope ratio. The allowable velocity field of the sliding surface model of the slope with sand gravel layer under overload action is established. The calculation formula of ultimate bearing capacity is obtained by using the upper limit method of limit analysis, and the results of indoor test and numerical simulation are compared with each other. It is concluded that the difference between the upper limit method and laboratory test is about 10.42% when the ultimate bearing capacity of sandy gravel layered slope is calculated under the action of overload, which has certain engineering practical value.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU43

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