ABSTRACT
The boundary element method (BEM) is the second most popular numerical method for engineering analyses after the finite element method (FEM). The method has applications in heat transfer, fluid flow, acoustics, and other physical phenomena, although the focus is on geomechanics. There are advantages with both methods. The main advantage of BEM is the reduced dimensionality of the problem because only the surfaces of excavations need to be discretized. However, BEM leads to a fully populated master stiffness matrix, which leads to problem size limitations, unlike FEM that leads to a sparsely populated master stiffness matrix. Discretizing only the surface of an opening makes mesh construction of complex shapes much easier. Two major disadvantages of BEM are coping with different rock types and deformation beyond the elastic limit. In rock mechanics, BEM is used mainly for linearly elastic, homogeneous material analyses.
