| 引用本文: | 马强,吴峰,肖衡林.土工格栅-玻璃砂界面细观特性离散元研究[J].哈尔滨工业大学学报,2019,51(8):151.DOI:10.11918/j.issn.0367-6234.201806138 |
| MA Qiang,WU Feng,XIAO Henglin.DEM study on interface performance of geogrid-reinforced glass sand[J].Journal of Harbin Institute of Technology,2019,51(8):151.DOI:10.11918/j.issn.0367-6234.201806138 |
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| 摘要: |
| 为分析剪切带的形成机制和演化机理,明确拉拔试验中筋土界面参数的宏细观联系,基于离散元数值方法,使用PFC2D软件模拟土工格栅加筋玻璃砂的拉拔试验,并与物理拉拔试验结果进行对比分析.在数值试验中采用分段函数重现格栅非线性应力-应变关系,根据玻璃砂颗粒位移值确定剪切带的平均厚度,重点分析剪切带内接触力链、颗粒位移、颗粒旋转等因素以及大主应力方向与细观组构参数的联系.结果表明,在格栅拉拔位移较小时,离散元数值方法能较好地分析玻璃砂与土工格栅界面之间的力学行为,试样宏观的体积剪胀主要受剪切带内颗粒的运动控制；通过PFC2D程序采用FISH语言开发的颗粒旋转颜色显示程序,显示格栅上下界面砂颗粒出现不同的旋转方式,颗粒位移和旋转形成了一个呈“锯齿”分布的剪切区,揭示颗粒位移和颗粒旋转是剪切带演化的重要特征；接触力的分布及其各向异性演化决定了试样宏观的力学性质和剪切带基本形状；整个拉拔阶段,剪切带内大主应力方向的偏转与接触力各向异性主方向的偏转呈相近趋势. |
| 关键词: 土工格栅 玻璃砂 格栅位移 剪切带 组构各向异性 |
| DOI：10.11918/j.issn.0367-6234.201806138 |
| 分类号:U441.3 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(51678223);湖北省中央引导地方科技发展专项(2018ZYYD005);湖北工业大学绿色工业引领计划(YXQN2017001) |
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| DEM study on interface performance of geogrid-reinforced glass sand |
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MA Qiang,WU Feng,XIAO Henglin
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(School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan 430068, China)
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| Abstract: |
| To analyze the formation and evolution mechanism of shear bands and clarify the macroscopic and microscopic relationship of the interface parameters of the soil in the pull test, by employing particle flow code (PFC 2D), geogrid-reinforced glass sand numerical pull-out tests were conducted on the basis of discrete element numerical simulation, whose results were compared with those of laboratory tests. In the numerical test, the nonlinear stress-strain relationship of the geogrid was reconstructed by using the piecewise function. According to the sand particle displacement, the average thickness of shear bands was determined. Factors such as contact force chain, particle displacement, and particle rotation as well as relations between the major principal stress direction and parameters of fabric anisotropy were analyzed. Results show that DEM could better analyze the mechanical behavior between the interface of the glass sand particles and the geogrid under small geogrid displacement, and volume dilatancy of the sample was mainly controlled by the motion of particles in shear zone. The program for Particle Rotation Color Displaying, developed by FISH language, showed that particles in the upper and lower interfaces of geogrid had different rotation modes and displacement and rotation of the particles formed shear zone with serrated distribution, which revealed that particle displacement and rotation were important characteristics of the evolution of shear band. The distribution of contact force and the evolution of fabric anisotropic determined the macroscopic mechanical properties and the basic shape of the shear band. During the shearing, the deflection of the direction of the major principal stress was similar to the orientation of contact force anisotropy in the shear band. |
| Key words: geogrid glass sand geogrid displacement shear band fabric anisotropy |
