不同水环境下土石混填路基力学特性研究

发布时间：2018-02-02 11:54

本文关键词： 路基土石混填体模型试验 p-s曲线破坏模式　出处：《湖南大学》2014年硕士论文　论文类型：学位论文

【摘要】：山体开挖而形成的土石混填体作为一种特殊的建筑材料在路基填筑中有着非常广泛的应用，特别是高填路基。与传统的填筑路基相比，土石混填路基不仅在高度上存在较大的差别，更重要的是土石混填体作为一种填料其工程力学特性比较复杂。进行工程建设时，客观要求采取有别于传统路基的实施可能、技术可行、经济合理的工程对策。首先，对不同水环境下的土石混填体进行大型三轴试验。试验结果表明：最佳含水量状态下土石混填体的应力应变曲线具有明显的非线性，未出现峰值；水对土石混填体的力学性质有着重要影响，含水量的增加使得土石混填体的强度下降明显。其次，，基于相似比理论，在特制的地槽内按照相同的标准制作了2组土石混填路基模型，分别在正常条件和洒水浸泡环境下对2组路基模型进行分级加载，直至发生破坏。试验结果表明：正常条件下土石混填路基模型可表现出较好的结构性，在达到极限荷载之前其p-s曲线近似呈线性发展，破坏具有突发性，且破坏面并非传统的圆弧滑动面；而水的存在对其沉降变形、承载力大小和破坏模式均有着非常显著的影响；同时，由于土石混填路基模型的坡面处于临空状态，当荷载比较大时加载板两侧会出现比较明显的应力扩散和影响深度不对称的情况。最后，本文采用ADINA有限元分析软件建立不同工况下的土石混填体的二维平面应变计算模型，分析不同工况下路基的工作性能及力学特性。并与本文的试验数据进行对比，二者吻合较好，充分证明了研究结果的可靠性，从而对实际工程设计计算具有一定的参考价值。
[Abstract]:As a special building material, the earth-rock mixed fill formed by mountain excavation has been widely used in subgrade filling, especially in high-fill subgrade, compared with the traditional filling subgrade. There are not only great differences in the height of earth-rock embankment, but also the complex engineering mechanical properties of earth-rock fill as a kind of filler. The objective requirement is to adopt engineering countermeasures which are different from the traditional roadbed, feasible in technology and reasonable in economy. Firstly, a large scale triaxial test was carried out on the soil-rock mixed fill under different water conditions. The experimental results show that the stress-strain curve of the soil-rock mixed fill has obvious nonlinearity under the optimum water content, and there is no peak value. Water has an important effect on the mechanical properties of soil-rock mixed fill, and the strength of soil-rock mixed fill decreases obviously with the increase of water content. Secondly, based on the similarity ratio theory, two groups of soil-rock mixed subgrade models were made in the special geosyncline according to the same standard. The two groups of embankment models were respectively loaded under normal conditions and sprinkler immersion environment. The test results show that the soil-rock embankment model can exhibit better structure under normal conditions, and the p-s curve develops linearly before the ultimate load is reached, and the failure is sudden. The failure surface is not the traditional arc sliding surface. The existence of water has a significant effect on the settlement deformation, bearing capacity and failure mode. At the same time because the slope of the soil-rock embankment model is in the condition of being empty the stress diffusion and the asymmetry of the influence depth will appear on both sides of the plate when the load is large. Finally, ADINA finite element analysis software is used to establish the two-dimensional plane strain calculation model of soil and rock mixed fill under different working conditions. The working performance and mechanical properties of the roadbed under different working conditions are analyzed and compared with the experimental data in this paper. The results are in good agreement with each other, which fully proves the reliability of the research results. Therefore, it has certain reference value to actual engineering design calculation.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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