Preserved structure modeling of soil-rock mixtures and physical cover generation based on finite element meshes

Abstract

Soil and rock mixture (SRM) is ubiquitous in nature and also an excellent engineering fill material. Accurate evaluation of mechanical characteristics of SRM is of vital importance in the analysis of stability and deformation. Unfortunately, the presence of mega blocks in SRM makes it impossible to grasp the real attributes of full graded SRM using indoor or in-situ experiments. Consequently, numerical methods, especially those three-dimensional methods, become crucial to the objective evaluation of SRM mechanical properties. However, even the most powerful and sophisticated mesh generators become too weak to produce even low-quality meshes of real SRM samples. Accordingly, the numerical manifold method (NMM) is an excellent tool for this purpose since it successfully throws off shackles of mesh generation. In this study, we first produce an SRM sample according to the given size distribution and content of rock blocks. Then, we employ a tetrahedron mesh to act as the mathematical cover of the SRM sample; the mesh does not match the SRM sample domain. Next, we utilize Boolean operations in Ansys to generate the physical cover of the SRM sample and the robustness of the program is hence ensured to the greatest extent. As a preliminary application, finally we demonstrate the permeability evaluation of SRM, indicating that even for those SRM samples that cannot be meshed with the most powerful mesh generator, the proposed procedure can easily arrive at their solutions.