颗粒破碎对砂土剪切性质影响的离散单元研究  

DEM Investigations of the Influence of Particle Crushing on the Shear Properties of Sands

作　　者：李永松[1,2] 周国庆[1] 陈国舟[1,2] 周杰[3] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008 [2]中国矿业大学力学与建筑工程学院,江苏徐州221008 [3]重庆交通大学土木建筑学院,重庆400074

出　　处：《土工基础》2011年第6期53-56,共4页Soil Engineering and Foundation

基　　金：国家自然科学基金项目(50974117);国家青年科学基金项目(E090705)

摘　　要：采用离散单元方法,建立了圆形颗粒、不破碎非圆形颗粒和破碎非圆形颗粒的数值试验模型,进行了砂土的双轴剪切试验,研究了颗粒破碎现象对砂土物理力学性质的影响,分析了颗粒破碎和颗粒形状对试样强度的影响以及围压对颗粒破碎性质的影响。研究结果表明:颗粒破碎现象严重影响砂土的峰值强度以及体积应变性质,并且低围压下颗粒形状对强度影响大于颗粒破碎,随着围压增大,颗粒破碎的影响逐渐增强;围压影响颗粒破碎发生的速率和最终的破碎率;由对颗粒破碎的位置和试样内位移场的追踪可得到颗粒破碎的细观演化规律及破碎带的分布范围,破碎带分布范围与围压有关。A numerical investigation model using the Discrete Element Method （DEM） was established by the particle flow codein two dimensions （PFC2D） to simulate the biaxial shear tests on non-crushable circular and non-circular particles and crushahle non-circular particles. Physical biaxial shear tests were also performed on the sand samples. The objective of biaxial shear testswith both numerical and physical models is to evaluate the effect of particle crushing on the geotechnical properties of granular soils. It is concluded that particle crushing positively affects the peak strength and volumetric strain of sand. The effect of par-ticle shape on shear strength is more significant at higher confining pressures than at lower confining pressures. The rate of particle crushing is strongly affeeted by the magnitude of the eonfining pressures. Based on the recorded location of the particlebreakage and on the distribution of the displacement field in the numerical simulations, the microscopic regularity of evolution of the particle crushing and the location of breakage zones were identified.

关 键 词：双轴试验 颗粒破碎 二维颗粒流 数值试验 

分 类 号：TU441[建筑科学—岩土工程] TB115[建筑科学—土工工程]