Micromechanical modeling of geomaterials is challenging because of the complex geometry of discontinuities and potentially large number of deformable material bodies that contact each other dynamically. In this study, we have developed a numerical approach for micromechanical analysis of deformable geomaterials with dynamic contacts. In our approach, we detect contacts among multiple blocks with arbitrary shapes, enforce different contact constraints for three different contact states of separated, bonded, and sliding, and iterate within each time step to ensure convergence of contact states. With these features, we are able to simulate the dynamic contact evolution at the microscale for realistic geomaterials having arbitrary shapes of grains and interfaces. We demonstrate the capability with several examples, including a rough fracture with different geometric surface asperity characteristics, settling of clay aggregates, compaction of a loosely packed sand, and failure of an intact marble sample. With our model, we are able to accurately analyze (1) large displacements and/or deformation, (2) the process of high stress accumulated at contact areas, (3) the failure of a mineral cemented rock samples under high stress, and (4) post-failure fragmentation. The analysis highlights the importance of accurately capturing (1) the sequential evolution of geomaterials responding to stress as motion, deformation, and high stress; (2) large geometric features outside the norms (such as large asperities and sharp corners) as such features can dominate the micromechanical behavior; and (3) different mechanical behavior between loosely packed and tightly packed granular systems.

由于不连续的几何形状复杂且动态地相互接触的可变形材料体的数量众多，因此对土工材料进行微机械建模非常具有挑战性。在这项研究中，我们开发了一种用于动态接触的可变形土工材料的微机械分析的数值方法。在我们的方法中，我们检测具有任意形状的多个块之间的接触，对分离，结合和滑动的三种不同接触状态施加不同的接触约束，并在每个时间步长内迭代以确保接触状态的收敛。有了这些功能，我们就可以在微观尺度上模拟具有任意形状的晶粒和界面的真实土工材料的动态接触演化。我们通过几个示例来演示该功能，包括具有不同几何表面粗糙度特征的粗大断裂，粘土聚集体的沉降，松散堆积的沙子的压实以及完整大理石样品的破坏。利用我们的模型，我们能够准确地分析（1）大位移和/或变形，（2）在接触区域累积的高应力过程，（3）高应力下的矿物胶结岩石样品的破坏，以及（ 4）故障后碎片化。分析强调了准确捕获（1）响应于运动，变形和高应力的应力的岩土材料顺序演化的重要性；（2）规范之外的大几何特征（例如大的凹凸和尖角），因为这些特征可支配微机械行为；