Capacity and limits of the finite element method in applying it to geotechnical problems

The capacity of numerical methods is very large. It covers complex geomtries, nonlinear material laws, excavating phases in tunnelling. The finite element methods has been developed from continuum theory. Hence, the method is readily applicable for materials like steel, salt-rock, fluids, sands, clays but less suitable for concrete, jointed rocks, discontinua. Real failure modes during excavation in rock are scarcely covered by the finite element approach but satisfactory results are obtained if stresses and deformations under working loads are of interest. Problems arising when results obtained by sophisticated analysis have to be interpreted by engineers not familiar with the method are discussed (“black box”).