CAJ | 학술논문

颗粒破碎是影响砂土宏-微观力学性质的重要因素。采用改进型的可破碎颗粒生成方法，通过设置不同强度的平行黏结键模拟不同强度的可破碎颗粒，并借用基于离散元方法（DEM）的双轴压缩试验详细研究了可破碎性土在剪切过程中颗粒破碎率/平均破碎程度、微观尺度上的能量耗散分配机制、剪切破碎带形成以及断裂键各向异性的演化过程。结果表明，颗粒破碎强烈地影响砂土在宏观尺度上的力学响应、颗粒尺度上的能量分配机制以及剪切过程中的颗粒的组织结构演化。颗粒破碎主要影响小应变阶段各能量耗散元的分配机制，而在临界状态下剪切带内的颗粒摩擦以及破碎耗能是消耗外界功的主要因素。数值结果亦表明，颗粒的破碎伴随着整个剪切过程，但破碎率的增长速度却随着剪切应变的发展逐渐降低。另外，在剪切过程中，对于低破碎性土，在临界状态下剪切破碎带基本形成，带内的原有组织结构被打乱，断裂键的各向异性也随之弱化。
과립파쇄시영향사토굉-미관역학성질적중요인소。채용개진형적가파쇄과립생성방법，통과설치불동강도적평행점결건모의불동강도적가파쇄과립，병차용기우리산원방법（DEM）적쌍축압축시험상세연구료가파쇄성토재전절과정중과립파쇄솔/평균파쇄정도、미관척도상적능량모산분배궤제、전절파쇄대형성이급단렬건각향이성적연화과정。결과표명，과립파쇄강렬지영향사토재굉관척도상적역학향응、과립척도상적능량분배궤제이급전절과정중적과립적조직결구연화。과립파쇄주요영향소응변계단각능량모산원적분배궤제，이재림계상태하전절대내적과립마찰이급파쇄모능시소모외계공적주요인소。수치결과역표명，과립적파쇄반수착정개전절과정，단파쇄솔적증장속도각수착전절응변적발전축점강저。령외，재전절과정중，대우저파쇄성토，재림계상태하전절파쇄대기본형성，대내적원유조직결구피타란，단렬건적각향이성야수지약화。
Detailed knowledge of crushability evolution and particle-scale energy allocation behavior under the influence of particle breakage is of fundamental importance to the development of micromechanics-based constitutive models of sands. This study reports original results of the particle development, energy input/dissipation and shear band formation of idealized crushable sands using 2D discrete elements simulations. Particle breakage is modeled as the disintegration of synthetic agglomerate particles which are made up of parallel-bonded elementary discs. Simulation results show that the particle crushability strongly affect the mechanical response in macroscopic level and energy allocation in particle-scale level of the soil both at small and large strains. The major role of particle breakage, which itself only dissipates a negligible amount of input energy, is found to advance the soil fabric change and promote the inter-particle friction dissipation. At large strains where particle breakage is greatly reduced, a steady energy dissipation by inter-particle friction and mechanical damping is observed. Furthermore, it is found that the amount of particle breakage keeps increasing during the whole shearing process;but the rate of particle breakage decreases gradually with the applied axial strain. And a clear shear band can be found in low-crushable soil and the anisotropy of the broken bonds becomes weaker and weaker as the development of shearing.