滚动机制对颗粒材料剪切带形成的影响

摘要

The macroscopic definition of effective strain was introduced to describe the emergence and development of shear bands in granular materials .Three different numerical tests (i .e .,free rolling test ,limiting rolling test and rolling resistance considered test ) using the discrete element method (DEM ) were conducted to simulate the mechanical response of granular specimens under stress .The progressive development of effective strain in the granular specimens was illus-trated to analyse the origination and evolution of shear bands .The results indicate that the evolution of shear bands in granular materials can be simulated more accurately in free rolling and rolling resistance considered tests ,while be hardly simulated when particle rolling is strictly prevented .In the case of particle rolling resistance ,the shear band evolution is more distinct as the evolution of the minor shear bands is limited while the major shear bands are preferably promoted .%从宏观角度引入颗粒集合体有效应变表述颗粒材料剪切带的形成，从细观上模拟颗粒材料自由滚动、限制滚动、考虑滚动机制三种情况在外荷载下的力学响应。通过分析追踪颗粒材料有效应变的变化，探讨了颗粒材料剪切带的发展和形成过程。结果表明：限制滚动下不能模拟剪切带的发展，考虑颗粒自由滚动及滚动机制能较好的模拟剪切带的发展。而强调滚动机制限制了次要剪切带，同时促进主要剪切带的发展，因而能更有效的描述剪切带的形成过程。