The aim of this study is to numerically investigate the influence of particle breakage on the mechanical behavior of granular materials using a discrete element method(DEM). To enable particle crushing, non-crushable ...The aim of this study is to numerically investigate the influence of particle breakage on the mechanical behavior of granular materials using a discrete element method(DEM). To enable particle crushing, non-crushable elementary particles are boned together to represents the granular aggregates which can be crushed when the external force exceeds its strength. The flaw of the aggregate was also modeled by randomly distributed void. Single particle crushing tests were carried out to determine the distribution of particle strength. The results of single particle crushing tests illustrate that the simulated single particle fracture strength and pattern agree well with the Weibull's distribution equation.Conventional oedometer tests, drained monotonic and cyclic triaxial tests were also carried out to investigate the crushing of the aggregates and the associated mechanical behaviors. The effect of confining pressure on the crushing of aggregates and the mechanical behavior was also analyzed. It was found that the peak stress and dilation decrease significantly when particle crushing was considered.The deformation behavior of the specimen is essentially controlled by two factors: particle rearrangement-induced dilation and particle crushing-induced contraction. The increase of permanent strain and the reduction of dilation were observed during cyclic loading and they tend to reach a stable state after a certain number of cycles. The crushing of aggregate is most significant in the first two cycles. The results also indicated that for the same axial strain the volumetric strain and the bound breakage in the cyclic loading tests are significantly larger than that in the monotonic loading tests,especially at high cyclic stress ratio.展开更多
基金Foundation item： Project（2012CB719803） supported by the National Basic Research Program of China Project（201011159098） supported by the Seed Funding for Basic Research Scheme from The University of Hong Kong, China
文摘实验室测试在 Toyoura 沙标本上被执行调查在浸透 S 的度之间的关系 < 潜水艇 class= “ a-plus-plus ” > r </sub>,B 值和 P 波浪速度 V < 潜水艇 class= “ a-plus-plus ” > p </sub> 。毛孔水(通风 de 的水或自来水) 和毛孔气体的不同类型(空气或公司 < 潜水艇 class= “ a-plus-plus ” > 象背压力的不同大小一样的 2 </sub>) 被用来完成不同 S < 潜水艇 class= “ a-plus-plus ” > r </sub>( 或 B 值) 。在 B 值和 V 之间的测量关系 < 潜水艇 class= “ a-plus-plus ” > p </sub> 不与理论预言一致。测量表演 V < 潜水艇 class= “ a-plus-plus ” > 在与通风 de 的水冲洗的标本的 p </sub> 价值独立于 B 值(或 S < 潜水艇 class= “ a-plus-plus ” > r </sub>) 并且总是在处于充分浸透的状况的附近。然而， V < 潜水艇 class= “ a-plus-plus ” > 在与自来水冲洗的标本的 p </sub> 价值与在 V 之间的关系的 B 值，而是形状增加 < 潜水艇 class= “ a-plus-plus ” > p </sub> 和 B 值与理论预言相当不同。对在实验室测量和理论预言之间的差异的可能的解释躺因为空气作为空气水泡并且因此在水里存在毛孔液体(空气水混合) 是异构的而不是同质在理论预言假定。
基金supported by National Natural Science Foundation of China(Grant Nos.51578413,51238009 and 41272291)the Fundamental Research Funds for the Central Universities
文摘The aim of this study is to numerically investigate the influence of particle breakage on the mechanical behavior of granular materials using a discrete element method(DEM). To enable particle crushing, non-crushable elementary particles are boned together to represents the granular aggregates which can be crushed when the external force exceeds its strength. The flaw of the aggregate was also modeled by randomly distributed void. Single particle crushing tests were carried out to determine the distribution of particle strength. The results of single particle crushing tests illustrate that the simulated single particle fracture strength and pattern agree well with the Weibull's distribution equation.Conventional oedometer tests, drained monotonic and cyclic triaxial tests were also carried out to investigate the crushing of the aggregates and the associated mechanical behaviors. The effect of confining pressure on the crushing of aggregates and the mechanical behavior was also analyzed. It was found that the peak stress and dilation decrease significantly when particle crushing was considered.The deformation behavior of the specimen is essentially controlled by two factors: particle rearrangement-induced dilation and particle crushing-induced contraction. The increase of permanent strain and the reduction of dilation were observed during cyclic loading and they tend to reach a stable state after a certain number of cycles. The crushing of aggregate is most significant in the first two cycles. The results also indicated that for the same axial strain the volumetric strain and the bound breakage in the cyclic loading tests are significantly larger than that in the monotonic loading tests,especially at high cyclic stress ratio.
