基于裂缝扩展的堆石料流变细观模型

根据堆石颗粒破碎具有时间效应的特点来研究堆石料的流变性质。首先建立了基于亚临界裂缝扩展的堆石流变细观模型；其次研究流变数值试验的模拟方法，确定合理的颗粒破碎模式，根据两步循环判定法的思想计算宏观时间，并编写了相应的颗粒流程序；最后结合室内流变试验，开展单轴压缩条件下数值流变试验，拟合室内流变试验曲线，确定细观参数。计算表明：数值试验与室内试验流变曲线发展趋势基本一致；颗粒破碎模式对结果有一定的影响，越接近块体实际情况，模拟结果越好；流变的大小主要由瞬时颗粒破碎决定；流变的长期性由微裂缝扩展导致的延时颗粒破碎造成。

Rheological model for rockfill based on sub-critical crack expansion theory

The rheological properties of rockfill are studied based on the time-dependent behaviors of particle breakage. Firstly, a microscopic rheological model for rockfill is established based on the theory of sub-critical expansion of cracks. Secondly, the reasonable crushing modes of particles are analyzed. Macro-time is calculated by means of the method of the two-step circulation decision, and the relevant programs of particle flow are compiled. Finally, a series of numerical tests are carried out in order to simulate the uniaxial numerical rheological tests based on the selected micro-parameters. The simulated results are partially compared with the laboratory experiments, and good agreement is achieved. The results and analysis show that the modes of particle breakage have influence on the simulated results, that is, the closer to the real particles, the better the simulated results. The magnitude of rheological deformation is mainly dependent upon the breakage of instantaneous particles, which is caused by the larger contact forces. The rheology results from the delayed breakage of particles induced by the extension of microscopic cracks.