Efficient and User Friendly 3D Simulations of Underground Excavations Using the Isogeometric Boundary Element Method

Using current approaches, which are almost entirely based on volume methods, 3D simulations of complex underground excavations can be cumbersome and time-consuming. This is because the rock mass, which for practical purposes is of infinite extent, has to be discretised. This leads to very large meshes, which have to be truncated at a distance assumed to be “safe”. Consequently, the demand for human and computer resources can be significant. To ascertain the quality of the result is difficult because it depends on the fidelity of the volume mesh and the truncation distance. The aim of this paper is to present a novel approach that does not require volume discretisation. Using the isogeometric boundary element method (IGABEM), only excavation surfaces need to be defined. The geometry of the excavations can be defined in a highly accurate and smooth manner with computer-aided design (CAD) data, eliminating the requirement for mesh generation. Volume effects, such as nonlinear, anisotropic, and heterogeneous ground conditions, as well as the effect of ground support, can be considered. On several examples, related to real projects, it is shown that excavations of high complexity can be simulated, and highly refined results can be obtained in a mesh-free setting.