土石混合体力学特性的颗粒离散元双轴试验模拟研究

发布时间：2018-01-21 08:48

本文关键词： 土力学土石混合体颗粒流碎石形状力学特性　出处：《岩石力学与工程学报》2015年S1期 　论文类型：期刊论文

【摘要】：土石混合体作为土体和碎石的混合体,其宏观力学特性与碎石特性密切相关。采用试验研究和数值模拟相结合的方法,对土石混合体的力学特性进行研究。基于FISH语言开发颗粒流的多边形碎石生成模块,通过室内试验校核颗粒流模型的细观参数,建立土石混合体双轴试验模型。提出以形状因子m作为衡量碎石磨圆度的指标,对碎石形状进行了量化。研究了碎石含量、强度、形状对土石混合体力学特性影响,探讨碎石对土体强度提高的细观原因,揭示土石混合料的强度指标随各主要影响因素的变化趋势。结果表明:碎石含量和强度越高,混合体的强度也越高,当含石量小于40%时,土石混合体的力学特性受土体主导;内摩擦角随着碎石含量增加而增大,而黏聚力却在减小;随着形状因子的增大,强度降低,黏聚力和内摩擦角均减小;土石混合体中应力分布不均,在碎石含量较高时,碎石形成骨架效应,承担了主要荷载。
[Abstract]:As a mixture of soil and gravel, the macroscopic mechanical properties of soil-rock mixture are closely related to the gravel properties. The method of combining experimental research with numerical simulation is adopted. Based on FISH language, the polygonal gravel generation module of particle flow is developed, and the mesoscopic parameters of particle flow model are checked through laboratory tests. The biaxial test model of soil-rock mixture is established. The shape factor m is proposed as the index to measure the roundness of gravel wear. The shape of crushed stone is quantified. The content and strength of crushed stone are studied. The influence of shape on the mechanical properties of soil-rock mixture is discussed, and the causes of the increase of soil strength by gravel are discussed. The results show that the higher the gravel content and strength, the higher the strength of the mixture, when the content of stone is less than 40. The mechanical properties of soil-rock mixture are dominated by soil. The internal friction angle increases with the increase of gravel content, but the cohesion force decreases. With the increase of the shape factor, the strength decreases, the cohesion force and the internal friction angle decrease. The stress distribution in the mixed soil and rock is uneven. When the content of crushed stone is high, the gravel forms skeleton effect and bears the main load.
【作者单位】：中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家重点基础研究发展计划(973)项目(2011CB710602) 中国科学院重点部署项目(KZZD-EW-05) 国家自然科学基金重点项目(51139004)
【分类号】：TU43
【正文快照】： 1引言土石混合体是一种土体与碎石的混合物[1]。天然形成的土石混合体多为残坡积物、崩坡积物和冲洪积物等,在三峡库区[2-3],川西及青藏高原,东南沿海福建、香港等地区广泛分布[4-6]。在工程建设过程中的土石坝、矿山开采产生的尾矿坝、排土场、碎石土地基、路基也存在大量的

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