| The propagation of stress waves and the formation of local shear bands in soil-rock mixed fill foundations during dynamic compaction are influenced by factors such as the content of rock blocks, their shapes, and spatial arrangements. This paper employs the Material Point Method (MPM) to model the dynamic compaction reinforcement process of these foundations. Initially, a set of irregular rock block particles is created using the polar radius Fourier series expansion method and positioned randomly within a rectangular area. Contact detection is performed using geometric methods, including the bounding box of the outer rectangle. The next step involves triangulating the generated geometric model and inserting regular points into the background grid. Material points that represent the continuum are selected based on their presence within triangular elements. Subsequently, the material points are categorized to distinguish between soil, rock blocks, and the compaction hammer, with distinct material properties assigned to create the MPM calculation model for the soil-rock mixed fill foundation. Results indicate that when impacted by the free-falling compaction hammer, stress waves are generated within the foundation, and the characteristics of the rock blocks affect their downward propagation. Upon reaching the base of the foundation, these waves reflect and gradually diminish. The stress wave induces greater susceptibility to shear failure in the soil surrounding the rock blocks, leading to the formation of localized shear bands. The foundation's bearing capacity improves as the content of rock blocks increases, which simultaneously reduces the area affected by the dynamic compaction reinforcement. Additionally, this study examines how varying the compaction hammer's aspect ratio and drop height influences impact energy and the hammer's drop depth, revealing that higher compaction energy significantly enhances compaction settlement. |
