含石量对土石混合体剪切特性影响的颗粒离散元数值研究

发布时间：2018-05-10 13:02

本文选题：土石混合体 + 颗粒流　；参考：《工程地质学报》2017年04期

【摘要】：采用基于PFC~(2D)接触黏结模型的离散元数值模型,探讨含石量变化对土石混合体剪切特性的影响。利用室内大型直剪试验对表征土石混合体细观力学性质的模型参数进行标定,模拟分析了4种不同含石量土石混合体在4种不同围压作用下的剪切特性。试验结果表明:相同法向应力作用下,含石量越高,峰值剪应力越大,达到峰值剪应力时的剪应变越大,软化后强度越高,剪胀特性越强,剪切"跳跃"现象越明显。土石混合体摩擦角随含石量增高而增大;黏聚力随含石量增高而减小,含石量超过50%后基本不变。相同含石量的土石混合体,法向应力越高,峰值剪应力越大,应变软化特性越强。土石混合体剪切过程中以克服摩擦能和应变能为主,动能变化几乎为零。
[Abstract]:In this paper, a discrete element numerical model based on PFC / 2D contact bonding model is used to study the influence of rock content on the shear characteristics of soil-rock mixture. The model parameters of meso-mechanical properties of soil-rock mixtures were calibrated by large direct shear tests in laboratory. The shear characteristics of four kinds of soil-rock mixtures with different rock contents under four different confining pressures were simulated and analyzed. The experimental results show that under the same normal stress, the higher the rock content, the greater the peak shear stress, the greater the shear strain, the higher the strength after softening, the stronger the shear expansion, and the more obvious the phenomenon of "jump" in shear. The friction angle of soil-rock mixture increases with the increase of rock content, and the cohesive force decreases with the increase of rock content, and remains unchanged when the rock content exceeds 50%. The higher the normal stress is, the greater the peak shear stress is and the stronger the strain softening is. In the shear process of mixed soil and rock, the friction energy and strain energy are mainly overcome, and the kinetic energy change is almost zero.
【作者单位】：重庆大学山地城镇建设与新技术教育部重点实验室;重庆大学土木工程学院;重庆市江津区建设工程质量监督站;重庆江北国际机场扩建指挥部;
【基金】：教育部留学回国人员科研启动基金资助项目资助
【分类号】：TU43

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