| 二维粒状材料双轴压缩试验研究 |
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| 引用本文： | 张雷,张连卫,张建民.二维粒状材料双轴压缩试验研究[J].岩土力学,2011,32(Z1):314-0320. |
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| 作者姓名： | 张雷 张连卫 张建民 |
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| 作者单位： | 1. 清华大学 水沙科学与水利水电工程国家重点实验室，北京 100084；2. 北京科技大学 土木与环境工程学院，北京 100083 |
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| 基金项目： | 国家自然科学基金项目(No.50979046) |
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| 摘 要： | 为了研究粒状材料的各向异性力学行为与细观组构演化之间的关系，采用自主研发的双轴压缩试验系统，以圆形和椭圆形截面的金属棒状材料组成的二维堆积体为试验对象，对不同大主应力方向角?（沉积面与大主应力作用面的夹角）的试样进行了各向等压、常侧向压力、等p剪切3种应力路径试验，并通过分析试样在不同变形阶段的数字照片得到了其细观组构演化规律。发现对于椭圆形截面的试样存在一个卓越剪切方向，随剪应变增大，颗粒长轴呈现出向该方向偏转的趋势，并且在大变形条件下沿该方向形成剪切带；卓越剪切方向与沉积面方向关系不大，而与大主应力作用面方向夹角约为45°+ /2， 为残余内摩擦角；随卓越剪切方向与沉降方向夹角的不同，颗粒偏转程度的不同是导致剪胀特性和峰值强度各向异性的主要原因
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| 关 键 词： | 粒状材料 各向异性 细观组构 双轴压缩 |
| 收稿时间： | 2011-01-27 |
Experimental study of 2D granular materials under biaxial compression |
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| ZHANG Lei,ZHANG Lian-wei,ZHANG Jian-min.Experimental study of 2D granular materials under biaxial compression[J].Rock and Soil Mechanics,2011,32(Z1):314-0320. |
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| Authors: | ZHANG Lei ZHANG Lian-wei ZHANG Jian-min |
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| Institution: | 1. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China; 2. School of Civil & Environment Engineering, University of Science and Technology Beijing, Beijing 100083, China |
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| Abstract: | In order to investigate the stress-strain behavior and its variation with the micro-fabric for granular materials, a series of tests and corresponding micro-fabric analyses were conducted on dimensional ideal 2D granular materials with circular and elliptical shapes of cross-section, which were prepared at different maximum principal stress direction angles δ, using the biaxial testing system under three different stress paths including isotropic compression, constant lateral pressure shearing and constant mean principal stress shearing. The anisotropic property in shear strength and dilatation induced by shear were presented and analyzed. Based on the experimental results and micro-fabric analyses, the following new findings involving the failure mechanism of granular materials were confirmed, including that: (1) There exists a preferred shear direction towards which the long axis direction of particles tend to rotate as shear strain increases; and along this direction a shear band will be triggered and finally formed under large shear strain. (2) This preferred shear direction is irrelevant to the bedding plane, and the angle of the bedding plane with the preferred shear direction is about equal to 45°+ /2, where is residual internal friction angle. (3) The effect of particle rolling on the shear failure becomes more significant with the increasing angle of the bedding plane with the preferred shear direction, and such difference in the effect of particle rolling is the main reason why there is the anisotropy shear strength and different dilatation induced by shear. |
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| Keywords: | granular materials anisotropy micro-fabric biaxial compression |
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