Composite infinite element analysis of unbounded two-phase media

This paper discusses the development and application of a mapped type composite infinite element for modelling the response of unbounded two-phase media. The coordinate ascent mapping technique which uses conventional shape functions and the Gauss-Legendre integration method has been used for the formulation. The element is constructed such that it preserves compatibility between variations in effective stress and pore pressure. This compatibility is a basic requirement for the composite element to accurately model the two-phase media. Numerical analyses of problems with unbounded saturated media using these elements have shown considerably improved predictions compared to conventional analyses. A subroutine listing is presented to demonstrate the implementation of the element in finite element programs.