含石量对千枚岩土石混合体剪切特性影响的颗粒流数值模拟  

Numerical Simulation of Influence of Rock Content on Shear Characteristics of Rock-rock Mixture by Particle Flow

作　　者：吴红波 李占甫 江山 徐良 莘子健 WU Hong-bo;LI Zhan-fu;JIANG Shan;XU Liang;SHEN Zi-jian(Anhui Traffic Control Construction Management Co.Ltd.,Hefei 230088,China;Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]安徽省交控建设管理有限公司,合肥市230088 [2]中国地质大学(武汉)工程学院,武汉市430074

出　　处：《公路》2023年第5期274-282,共9页Highway

基　　金：安徽省交控建设管理有限公司科技项目,项目编号JKKY-2021-04。

摘　　要：以湖北宜巴高速咸池沟大桥下游处渣场中的千枚岩弃渣为研究对象,结合室内大型三轴试验,基于离散元软件PFC 3D,建立了大型三轴剪切试验数值模型,从宏观和细观角度分析了含石量对土石混合体剪切特性的影响以及试样变形破坏的机理。试验结果表明:试样的内摩擦角随含石量的增加而增加,黏聚力则随着含石量的增加呈现出先增加后减小的趋势,在50%含石量处取得最大黏聚力;剪切过程中试样的体应变表现为先剪缩后剪胀,含石量越高,剪胀性越强;从细观尺度上揭示了土石混合体在剪切中变形破坏的机理,初期的剪缩是由于加载板向下移动,试样被压密、高度减小所致,剪切中后期试样中部的颗粒朝向与竖直方向呈约45°的方向向两侧运动,形成两个共轭剪切带,试样在宏观上表现剪胀,随着含石量的增加,试样中部颗粒运动的速度更快,宏观表现出的剪胀性越显著。Relying on the phyllite waste slag in the downstream dump area of Xianchigou Bridge of the Yichang-Badong Expressway as the research object,combined with the indoor large-scale triaxial test,based on discrete element software PFC3D,large-scale triaxial shear test numerical model is established.The influence of rock content on shear properties of soil-rock mixture and the mechanism of deformation and failure of sample are analyzed from macroscopic and mesoscopic perspectives.The numerical test results show that with the increase of rock content,the internal friction angle increases with the increase of gravel content,while the cohesion increases first and then decreases with the increase of gravel content,and the maximum cohesion is achieved at 50%gravel content.During the shear process,the bulk strain of the sample is first contracted and then dilated.The higher the gravel content is,the stronger the dilatancy is.The mechanism of deformation and failure of soil-rock mixture in shear is revealed from the meso-scale.Initial shear shrinkage is due to the loading plate moving down,the sample is reduced by pressure height.In the middle and late stages of shear,the particle orientation in the middle of the sample and the vertical direction moves to both sides in a direction of about 45°,forming two conjugate shear bands.The sample shows dilatancy on the macro level.With the increase of gravel content,the particle movement speed in the middle of the sample is faster,and the dilatancy on the macro level is more significant.

关 键 词：隧道弃渣 千枚岩 土石混合体 大三轴试验 离散元模拟 含石量 

分 类 号：TU411.3[建筑科学—岩土工程] U416.11[建筑科学—土工工程]