土石混合体的剪切面分形特征及强度产生机制
发布时间：2018-10-10 08:12
【摘要】：基于考虑含石量、含水率、块石岩性、初始孔隙比、法向压力5个影响因素的土石混合体室内大型直剪试验,利用剪切面在分形几何学上的统计规律和颗粒流数值模拟方法得到的直剪试验中颗粒的相互作用规律,对土石混合体的抗剪强度产生机制进行研究。结果表明:(1)土石混合体的剪切面呈不规则的起伏形态与块石的存在关系密切,且具有较好的分形特征,分形维数随着含石量和块石强度的增大、含水率和法向压力的减小均呈增大趋势;(2)含石量高于40%时,黏聚力小于30 k Pa;(3)内摩擦角随着含石量的增大、块石强度的增大、含水率的降低、初始孔隙比的降低、法向压力的降低均呈增大规律,且与分形维数满足正相关函数关系;(4)块石附近应力集中较明显,剪切过程中,颗粒间的接触力主要通过迎着剪切方向的接触面传递,而背着剪切方向的颗粒接触面基本不传递力;(5)内摩擦角φ等于剪切面上与颗粒本身接触性质有关的接触面内摩擦角θ0和与剪切面分形维数有关的接触面倾角θi之和,利用此机制可解释直剪试验中强度参数的变化规律。
[Abstract]:Based on the laboratory direct shear test of soil-rock mixture considering five factors including rock content, water content, block lithology, initial void ratio and normal pressure, Based on the statistical law of shear surface in fractal geometry and the interaction law of particle in direct shear test, the mechanism of shear strength of soil-rock mixture is studied. The results show that: (1) the shear surface of soil-rock mixture is closely related to the existence of massive rock and has good fractal characteristics, and the fractal dimension increases with the increase of rock content and rock strength. (2) when the rock content is higher than 40, the cohesion force is less than 30 k Pa; (3) the internal friction angle increases with the increase of rock content, the strength of block rock increases, the water content decreases, and the initial porosity decreases. The decrease of normal pressure increases and the fractal dimension satisfies the positive correlation function. (4) the stress concentration near the block rock is obvious, and the contact force between particles is mainly transmitted through the contact surface in the direction of shear during shear. (5) the internal friction angle 蠁 is equal to the sum of the internal friction angle 胃 _ 0 of the contact surface related to the contact property of the particle itself and the dip angle 胃 _ I of the contact surface related to the fractal dimension of the shear surface. This mechanism can be used to explain the variation of strength parameters in direct shear test.
【作者单位】： 重庆大学土木工程学院;重庆大学山地城镇建设与新技术教育部重点实验室;
【基金】：国家自然科学基金资助项目(51108485,41372356) 高等学校博士学科点专项科研基金资助项目(20110191120033)~~
【分类号】：TU411.7
本文编号：2261285
[Abstract]:Based on the laboratory direct shear test of soil-rock mixture considering five factors including rock content, water content, block lithology, initial void ratio and normal pressure, Based on the statistical law of shear surface in fractal geometry and the interaction law of particle in direct shear test, the mechanism of shear strength of soil-rock mixture is studied. The results show that: (1) the shear surface of soil-rock mixture is closely related to the existence of massive rock and has good fractal characteristics, and the fractal dimension increases with the increase of rock content and rock strength. (2) when the rock content is higher than 40, the cohesion force is less than 30 k Pa; (3) the internal friction angle increases with the increase of rock content, the strength of block rock increases, the water content decreases, and the initial porosity decreases. The decrease of normal pressure increases and the fractal dimension satisfies the positive correlation function. (4) the stress concentration near the block rock is obvious, and the contact force between particles is mainly transmitted through the contact surface in the direction of shear during shear. (5) the internal friction angle 蠁 is equal to the sum of the internal friction angle 胃 _ 0 of the contact surface related to the contact property of the particle itself and the dip angle 胃 _ I of the contact surface related to the fractal dimension of the shear surface. This mechanism can be used to explain the variation of strength parameters in direct shear test.
【作者单位】： 重庆大学土木工程学院;重庆大学山地城镇建设与新技术教育部重点实验室;
【基金】：国家自然科学基金资助项目(51108485,41372356) 高等学校博士学科点专项科研基金资助项目(20110191120033)~~
【分类号】：TU411.7
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