堆石料缩尺效应的细观机制研究

MESOSCOPIC MECHANISM STUDY OF SCALE EFFECTS OF ROCKFILL

堆石料的缩尺效应是客观存在的,受众多因素的影响,不同学者的试验结果均不相同甚至规律相反。采用考虑颗粒破碎效应的随机颗粒不连续变形方法,探讨堆石料缩尺效应的细观机制,试图解释试验成果出现差异的原因。主要研究压实度控制标准和颗粒自身性质对缩尺效应的影响,模拟结果表明:颗粒形状和级配对堆石料的压实性能有很大的影响,因此采用相对密度控制的缩尺级配料的密实度其强度差异较小;最大粒径越大,堆石料的不均匀系数越大,颗粒间的咬合作用越强烈,导致堆石料的初始切线模量也增大;而堆石料强度的缩尺效应与缩尺方法、压实度控制标准和颗粒自身性质等因素有关,其细观机制在于颗粒的剪胀、破碎和重排列受上述因素的影响而产生此消彼长或者此长彼消的复杂关系,其最终结果取决于何种因素占据主导地位;并试图提出一个通用的缩尺效应模型描述缩尺级配料的力学特性变化规律,外推原型级配料的力学参数不太可能,只能针对特定堆石料展开研究。

The scale effect of rockfill exists objectively and is influenced by many factors.The existing test results conducted by different researchers show different and even reverse trends.By employing the stochastic granular discontinuous deformation method（SGDD） considering particle breakage,the mesoscopic mechanism of rockfill scale effects is studied,and attempting to explain the reasons leading to different test results.This research mainly focuses on the effects of degree of compaction control standard and particle properties on scale effects of rockfill.The simulation results show that particle shape and grading have great influence on compaction capacity of rockfill,so the degree of compaction controlled by relative density is much more reasonable.With the increasing of maximum particle size,the uniformity coefficient of rockfill increases;particles provide a higher degree of interlocking and bring about a higher initial tangent modulus.The scale effects on rockfill strength is much more complicated,which is related with scaling method,degree of compaction control standard and particle.s own properties.The shear strength of rockfill comes from shear dilation,particle breakage and particle rearrangement.Under the influences of external factors,these three mechanisms of action will eliminate and replace each other.The final response depends on which factor is dominant.The attempt to find a universal model to describe the properties of scaled rockfill and to extrapolate the mechanical parameters of prototype rockfill is rarely practical.The research aimed at specific rockfill can be conducted.