Fast iterative solution of large soil-structure interaction problems in varied ground conditions

Abstract

Many geotechnical problems involve a wide range of materials with vast difference in stiffness and permeability resulting in an ill-conditioned system. Existing practical preconditioners perform poorly for such problems while incomplete factorization preconditioners may show signs of instability. Recent advances in preconditioning show that the inexact block diagonal preconditioners are much less sensitive to any difference in such material properties for the iterative solution of soil-structure interaction problems. This paper highlights the general applicability of such preconditioners to large-scale geotechnical problems in realistic ground conditions with the help of a user defined solver interface in the commercial GeoFEA software. The practical observation is that nonhomogeneous soil and structural elements do not impose a problem for the new preconditioners. In fact, they can be even more effective as the system accumulates more and more stiff soil and/or structural elements.