作为典型的非连续介质，离散颗粒材料的蠕变行为对滑坡、泥石流等地质灾害的形成与演化具有重要影响。然而，关于颗粒粒径与偏应力之间的交互作用机制及其对蠕变行为影响的系统研究仍显不足。为揭示颗粒粒径与偏应力对蠕变行为的耦合作用机制，该研究开展了多工况下二氧化硅圆珠颗粒的室内蠕变试验，系统分析了不同粒径与偏应力对颗粒材料蠕变特性的影响规律。基于Derec蠕变模型并结合试验结果，构建了颗粒材料蠕变状态的定量化计算模型，阐明了粒径对系统蠕变参数的调控机制。结果表明，颗粒系统的蠕变行为本质上是颗粒内部变形与其抵抗变形能力之间动态平衡的体现。蠕变参数通过调控颗粒间滑移与爬行行为，对系统的蠕变特性产生显著影响。具体表现为，随着颗粒粒径的增大，系统的蠕变值显著提高，更易进入类液态的流动状态，同时系统的抗变形能力减弱，并表现出对偏应力更高的敏感性。同时发现，颗粒粒径的增大不仅显著提升了颗粒体系的流动性，还增强了其对偏应力变化的敏感性。较大粒径颗粒在高偏应力条件下的响应更为显著，颗粒材料的流动特性亦更易受到粒径变化的影响。这种影响表现为颗粒粒径与系统初始状态参数及特征应变呈正相关关系，而与粘滞系数、临界蠕变速度和临界蠕变应力呈负相关关系。

As a typical discontinuous medium, discrete granular materials’ creep behavior plays a crucial role in the formation and evolution of geological disasters such as landslides and debris flows. However, systematic research on the interaction mechanism between particle size and deviatoric stress and its impact on creep behavior remains insufficient. To reveal the coupled effects of particle size and deviatoric stress on creep behavior, this study conducted indoor creep tests on silica spherical particles under multiple conditions and systematically analyzed the influence patterns of different particle sizes and deviatoric stresses on the creep characteristics of granular materials. Based on the Derec creep model and experimental results, this study constructed a quantitative computational model of the creep state of granular materials and clarified the regulatory mechanism of particle size on the creep parameters of the system. The results indicate that the creep behavior of granular systems essentially reflects the dynamic balance between internal deformation and resistance to deformation within the particles. Creep parameters significantly influence system creep characteristics by regulating particle slip and creep behavior. Specifically, as particle size increases, the creep value of the system increases markedly, making it more prone to entering a liquid-like flow state. Concurrently, the system’s resistance to deformation declines while exhibiting heightened sensiti-vity to deviatoric stress. Furthermore, an increase in particle size not only significantly enhances the fluidity of the particle system but also amplifies its sensitivity to changes in deviatoric stress. Particles with larger diameters show a more pronounced response under high deviatoric stress conditions, and the flow characteristics of granular mate-rials are more susceptible to particle size variations. This influence manifests as a positive correlation between particle size and both the system's initial state parameters and characteristic strain, while exhibiting negative correlations with viscosity coefficient, critical creep velocity, and critical creep stress.