摘要
基于泥质粉砂岩室内双轴压缩试验,建立PFC2D颗粒流数值模型,以此来探究泥质粉砂岩破坏的细观机理。考虑组成泥质粉砂岩试样的颗粒形状,根据电镜扫描图勾选出5种典型颗粒形状,与圆形颗粒一起生成给定孔隙率的稳定数值试样。颗粒间选用平行粘结接触模型,选取弹性模量、泊松比、峰值应力分别对饱和、天然状态的泥质粉砂岩试样进行不同围压下的细观参数标定,然后进行双轴压缩试验模拟,分析试样在双轴压缩试验过程中颗粒法向接触力、切向接触力、配位数、孔隙率等细观组构参数的分布特征和演化规律。试验结果表明:双轴压缩试验的细观参数标定可不考虑抗剪强度指标黏聚力c和内摩擦角Φ值的影响。破坏前后,试样各方向统计范围内都存在法向接触力和切向接触力。围压的存在影响试样的起始配位数、孔隙率和试样破坏后的稳定配位数和孔隙率,对配位数和孔隙率的改变速率影响很小。试样空间孔隙率的演化在一定程度上反映了试样破坏时内部结构的变迁,能更加直观地反映试样的破坏模式。
Based on the indoor biaxial compression test of argillaceous siltstone,a numerical model of PFC2 D particle flow was established.The model considered the particle shape of the argillaceous siltstone samples.Five typical particle shapes were selected according to the scanning electron microscope,and the circular particles were selected.A stable numerical sample of a given porosity was randomly generated together.The parallel bond contact model was selected between the particles,and the elastic modulus,Poisson’s ratio and peak stress were selected to calibrate the meso-parameters of the saturated and natural argillaceous siltstone samples under different confining pressures,and then the biaxial compression test was carried out.The simulation analysis of the distribution characteristics and evolution of the meso-structure parameters such as particle normal contact force,tangential contact force,coordination number and porosity during the biaxial compression test were analyzed.The test results show that the meso-parameter calibration of the biaxial compression test can ignore the influence of the shear strength indicators c andΦ.Before and after the failure,the normal contact force and the tangential contact force existed between the particles in the statistical range of the sample in all directions.The presence of confining pressure affects the initial coordination number of the sample,the porosity and the stable coordination number and porosity after the sample is destroyed,and has little effect on the rate of change of coordination number and porosity.The evolution of the spatial porosity of the sample reflects the change of the internal structure when the sample is destroyed to a certain extent,which can reflect the failure mode of the sample more intuitively.
作者
肖尊群
王鑫
汤东桑
董琼英
姜亦男
杨凯
曹童童
邓震
XIAO Zunqun;WANG Xin;TANG Dongsang;DONG Qiongying;JIANG Yinan;YANG Kai;CAO Tongtong;DENG Zhen(Xingfa School of Mining Engineering,Wuhan Institute of Technology,Wuhan 430000,China;School of Civil Engineering and Architecture,Wuhan Institute of Technology,Wuhan 430000,China;China Petroleum Pipeline Anti-corrosion Engineering Co.Ltd.,Langfang 065000,China)
出处
《煤田地质与勘探》
CAS
CSCD
北大核心
2020年第2期161-170,共10页
Coal Geology & Exploration
基金
国家自然科学基金项目(51804222)。
关键词
双轴压缩试验
微观组构
切向接触力
法向接触力
配位数
细观参数
演化
biaxial compression test
microstructure
tangential contact force
normal contact force
coordination number
mesoscopic parameters
evolution
作者简介
第一作者:肖尊群,1982年生,男,湖北武汉人,博士,副教授,从事岩体力学、土动力学方面的研究工作.E-mail:547309418@qq.com;通信作者:王鑫,1995年生,男,湖北十堰人,硕士研究生,从事岩体力学方面的研究.E-mail:1024028184@qq.com。
