等应力比加载路径下堆石料力学特性的细观数值分析

Meso-Scale Numerical Analysis on Mechanical Properties of Rockfill Under Loading Path of Constant Stress Ratio

堆石料的力学特性与应力路径相关,而常规三轴试验的应力路径与堆石坝工程填筑期坝体内的应力路径差别较大,因此本文采用考虑颗粒破碎效应的随机颗粒不连续变形分析(SGDD)方法进行等应力比加载路径下堆石料三轴试验的细观数值模拟,研究固结应力和加载应力比对堆石料强度和变形特性的影响.模拟结果表明:固结应力和加载应力比对堆石料的力学特性影响较大,随着固结应力的增加、加载应力比的减小,应力应变曲线由应变软化型向硬化型转化,试样也由低压剪胀向高压剪缩转变;p-q平面内的强度包络线具有明显的非线性;细观组构量的演化规律与堆石料的宏观力学特性密切相关.

The mechanical properties of rockfill are dependent on stress path, while the stress path in conventional triaxial test is different from that of rockfill during dam construction. Regarding this, the stochastic granular discon-tinuous deformation（SGDD）method is employed to study the rockfill at mesomechanical level. This study is aimed at exploring the relationship between the consolidation stress, loading stress ratio and macroscopic response of rock-fill.Simulation results show that the consolidation stress and loading stress ratio exert a significant impact on the strength and deformation characteristics of rockfill. As the consolidation stress increases and loading stress ratio de-creases,the type of stress strain relationship transfers from strain softening to hardening, meanwhile,the volumetric response transfers from dilation at low confining pressure to compaction at high confining pressure. The strength enve-lope inp-q plane shows obvious non-linear features. The evolution of mesoscopic fabric exhibits good uniformity with macroscopic response of rockfill.