土石混填路基工程特性及其稳定性分析

发布时间：2018-01-06 20:07

本文关键词：土石混填路基工程特性及其稳定性分析　出处：《湖南大学》2016年硕士论文　论文类型：学位论文

【摘要】：土石混填体是一种由土体和块石混合形成的非均质散体材料,广泛应用于山区、丘陵地带的公路建设之中,其工程力学特性也备受人们的关注。由于该材料具有物质组成的复杂性,结构分布的不规则性,给其工程力学特性研究和工程应用带来了极大的困难。国内外众多学者对其力学特性、路用性能等进行了一系列的试验与理论研究,也得出了较多的研究成果。但各研究成果之间难以互相对比,且在工程实践中还存在着较多的问题和不足,有待于进一步完善和发展。首先,对土石混填体的路用性能进行研究,主要包括土石混填体的颗粒组成、颗粒级配以及击实特性等。由此了解土石混填体的路用性质,并获得不同颗粒组成条件下的压实最佳含水率与最大干密度,为后续的土石混填体大型直剪试验的试样制作提供依据。其次,基于室内大型直剪试验,在前人研究的基础上,考虑级配参数的影响,通过控制试样质量与体积达到试验所需的压实度水平,分析了各主要参数对土石混填体抗剪强度的影响规律。试验结果表明:在级配良好的情况下,含石量在50%~80%范围内,土石混填体的抗剪强度随着含石量的增加而增加。基于matlab多元线性回归分析,得出了各因素对土石混填体抗剪强度影响程度的主次顺序为:含石量含水率压实度不均匀系数曲率系数,通过非线性回归分析得到了其抗剪强度关于各因素的拟合公式,且相关指数R2大于0.9。最后,利用直剪试验得出的土石混填体抗剪强度指标,基于强度折减有限元法对土石混填体路基边坡稳定性进行分析,并探讨不同含石量情况对土石混填体路基边坡稳定安全系数和最危险滑动面的影响。得到如下结论:随着土石混填体含石量的增加,边坡进入极限状态时的最大应力值和最大拉应力值在逐渐增大,而其最大塑性应变与最大位移值均逐渐减小。边坡的安全系数也随含石量的增加而逐渐提高,呈现非线性增长趋势,且当土石混填体的含石量从50%增长到60%时,路基边坡安全系数的提高较为明显。
[Abstract]:Soil-rock fill is a kind of heterogeneous bulk material formed by mixing soil and rock. It is widely used in highway construction in mountainous and hilly areas. Due to the complexity of the material composition and the irregularity of the structure distribution, the engineering mechanical properties of the material are also concerned. Many scholars at home and abroad have carried out a series of experimental and theoretical research on its mechanical properties and road performance. Also got more research results. But the research results are difficult to compare with each other, and there are still many problems and deficiencies in engineering practice, which need to be further improved and developed. First of all. The road performance of soil-rock mixed fill is studied, including the particle composition, particle gradation and compaction characteristics of soil-rock mixed fill, and the road properties of soil-rock mixed fill are understood. The optimum moisture content and maximum dry density of compaction under different particle composition conditions are obtained, which provides the basis for the subsequent large-scale direct shear test of earth-rock fill. Secondly, it is based on indoor large-scale direct shear test. On the basis of previous studies, considering the influence of gradation parameters, the quality and volume of the sample are controlled to reach the required compaction level of the test. The influence of main parameters on the shear strength of earth-rock mixed fill is analyzed. The experimental results show that the rock content is in the range of 50% or 80% under the condition of good gradation. The shear strength of earth-rock mixed fill increases with the increase of rock content, based on matlab regression analysis. It is concluded that the primary and secondary order of the influence of various factors on the shear strength of the earth-rock mixed fill is: the coefficient of curvature of the uneven coefficient of compaction of the water content of the rock content. Through nonlinear regression analysis, the fitting formula of shear strength on various factors is obtained, and the correlation index R2 is greater than 0.9.Finally, the shear strength index of earth-rock mixed fill is obtained by direct shear test. Based on the strength reduction finite element method, the stability of embankment slope is analyzed. The influence of different rock content on the stability safety factor and the most dangerous sliding surface of the embankment slope is discussed. The conclusion is as follows: with the increase of the rock content of the earth-rock mixed fill. When the slope enters the limit state, the maximum stress value and the maximum tensile stress value are gradually increasing, while the maximum plastic strain and the maximum displacement value are gradually decreasing. The safety factor of the slope also increases with the increase of the rock content. The slope safety factor of embankment slope is improved obviously when the rock content of soil and rock mixed fill increases from 50% to 60000.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U416.1

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