The creep and stress relaxation behaviors under the triaxial shearing of an idealized granular soil were studied using the three-dimensional discrete element method, into which the rate process theory was incorporated to enable simulation of these two time-dependent physical processes by a high-performance computing facility. The model was validated by comparing the simulation results with published experimental data. The study is focused on the effects of deviatoric stress during triaxial shearing of the granular soils on their creep and stress relaxation behaviors. In particular, to gain insights into their micromechanical mechanisms, a careful examination was made of the relationship between the shear-strain localizations occurring during creep and triaxial shearing, and the evolution of the contact number, average contact forces, and shear-induced anisotropies during these two time-dependent processes. The results indicate that the deviatoric stress level strongly affects the rates of creep strain and stress relaxation and dictates whether creep rupture will occur. These two time-dependent processes of the granular soil are also found to be isotach, which is evidenced by a unique normalized stress–strain relationship derived from the creep and stress relaxation tests.

使用三维离散元方法研究了理想化颗粒状土在三轴剪切下的蠕变和应力松弛行为，并结合了速率过程理论以通过高性能模拟这两个时间相关的物理过程计算设施。通过将仿真结果与已发布的实验数据进行比较，对模型进行了验证。该研究的重点是颗粒土在三轴剪切过程中的偏应力对其蠕变和应力松弛行为的影响。特别是，为了深入了解它们的微机械机理，我们仔细研究了蠕变和三轴剪切过程中发生的剪切应变局部化与接触数，平均接触力的演变之间的关系，和这两个时间相关过程中的剪切引起的各向异性。结果表明，偏应力水平强烈影响蠕变应变和应力松弛的速率，并决定是否会发生蠕变破裂。还发现这两个随时间变化的粒状土壤过程是等渗线，这通过蠕变和应力松弛测试得出的独特的归一化应力-应变关系得到了证明。