基于离散元法进行砂土直剪试验模拟与剪切宏细观响应研究。采用试样分条带法研究砂土剪切过程中的变形发育情况;记录应力-位移关系,分析砂土剪切应力、应变特性与剪胀特性。通过分析接触力链、接触组构分布、配位数及滑动接触百分比等细观行为演化研究颗粒细观接触状态演变;基于局部孔隙率变化分析颗粒细观分布状态演变;采用颗粒累积转动量和速度场分析颗粒细观运动状态及剪切带发育的细观机制;对离散元软件PFC2D进行二次开发,实现主应力的可视化。研究表明应变局部化集中于颗粒转动、接触滑动、体胀明显的剪切带内,剪切带内外颗粒不同的运动状态导致细观参量的变化,剪切带厚度为(10~15)d50;力链网络、接触组构和主应力场本质上是一致的,三者主方向在剪切过程中发生了近似一致的偏转。
Abstract
Direct shear test of sand was simulated using discrete element method and the macro-and-mesoscopic responses of sand during shearing were analyzed in this research. The development of sand deformation was observed through strip partition method; and the relationship between shear stress and shear displacement was recorded to analyze the macroscopic behaviors of sand. In mesoscopic scale, the development of contact status was researched through analyzing contact force chain, contact fabric distribution, coordination number and sliding contact percentage; the evolution of granular distribution under shearing was observed through the analysis of porosity variation;
关键词
砂土 /
离散元法 /
直剪试验 /
细观力学 /
剪切带
Key words
sand /
discrete element method /
direct shear test /
meso-mechanics /
shear band
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参考文献
[1] 史旦达, 周 健, 刘文白, 等. 砂土直剪力学性状的非圆粒模拟与宏细观机理研究[J]. 岩土工程学报, 2010, 32(10): 1557-1565.
[2] 蔡正银, 李相崧. 无黏性土中剪切带的形成过程[J]. 岩土工程学报, 2003, 25(2) : 129-134.
[3] 张 兆, 刘元雪. 应变局部化理论及在岩土工程中的应用[J]. 后勤工程学院学报, 2004, (2):12-15.
[4] 刘文白, 张 辉, 邓一兵. 基于DPDM技术的砂土直剪试验剪切过程中的应力场分析[J]. 中国水运, 2008, 8(7): 235-239.
[5] POTTS D M, DOUNIAS G T, VAUGHAN P R. Finite Element Analysis of the Direct Shear Box Test[J]. Geotechnique, 1987, 37(1): 11-23.
[6]TEJCHMAN J, BAUER E. FE-simulation of a Direct Shear and a True Simple Shear Test within a Polar Hypoplasticity[J]. Computers and Geotechnics, 2005, 32(1):1-16.
[7] THORNTON C, ZHANG L. Numerical Simulation of the Direct Shear Test[J]. Chemical Engineering and Technology, 2003, 26(2): 153-156.
[8] LIU S H, SUN D A, MATSUOKA H. On the Interface Friction in Direct Shear Test[J]. Computers and Geotechnics, 2005, 32(5):317-325.
[9] MASSON S, MARTINEZ J. Micromechanical Analysis of the Shear Behavior of a Granular Material[J]. Journal of Engineering Mechanics, 2001, 127(10): 1007-1016.
[10]WANG J, GUTIERREZ M. Discrete Element Simulation of Direct Shear Specimen Scale Effects[J]. Geotechnique, 2010, 60(5): 359-409.
[11]蒋明镜, 王富周, 朱合华. 单粒组密砂剪切带的直剪试验离散元数值分析[J]. 岩土力学, 2010, 31(1): 253-257.
[12]MISHRA B K, MEHROTRA S P. Modeling of Particle Stratification in Jigs by the Discrete Element Method[J]. Minerals Engineering, 1998, 11(6): 511-522.
[13]ODA M. Initial Fabrics and Their Relations to Mechanical Properties of Granular Material[J]. Soils and Foundations, 1972, 12(1):17-36.
[14]ROTHENBRUG L, BATHURST J. Analytical Study of Induced Anisotropy in Idealized Granular Materials[J]. Geotechnique, 1989, 39(4):601-614.
[15]刘 洋, 吴顺川, 周 健. 单调荷载下砂土变形过程数值模拟及细观机制研究[J]. 岩土力学, 2008, 29(12): 3199-3204.
基金
国家自然科学基金项目(51178044);北京高校青年英才计划资助项目(YETP0340)
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