This paper presents a theoretical study on a hybrid fabric evolution law for modelling anisotropic behaviour of granular media. In the hybrid evolution law, the rate of a contact normal-based fabric tensor is related to the rates of both stress ratio tensor and plastic strain. Assumptions and principles that were adopted for the development of the fabric evolution law are presented and discussed at first. Its accuracy is then examined by comparing with discrete element modelling (DEM) results under proportional loading and experimental data under complex loading and unloading processes. It is found that fabric evolution at low stress ratios is closely related to the stress-rate driven term of the hybrid law, while the strain-rate driven term dominates at high stress ratios. The hybrid evolution law satisfies the uniqueness requirement of fabric at the critical state by introducing an ‘attractor’ concept. Overall, fabric evolutions predicted by the hybrid law show a close agreement with DEM simulation results and experimental data.

本文提出了一种用于模拟粒状介质各向异性行为的混合织物演化规律的理论研究。在混合演化定律中，基于接触法线的织物张量的比率与应力比张量和塑性应变的比率有关。首先介绍并讨论了用于制定织物演化定律的假设和原则。然后，通过与比例加载下的离散元素建模（DEM）结果以及复杂加载和卸载过程下的实验数据进行比较，来检验其准确性。发现低应力比下的织物演化与混合定律的应力率驱动项密切相关，而应变率驱动项在高应力比下占主导地位。混合进化定律通过引入“吸引子”概念来满足临界状态下织物的唯一性要求。总体而言，混合定律预测的织物演变与DEM模拟结果和实验数据非常吻合。