Finite element simulation for rock salt with dilatancy boundary coupled tofluid permeation

This contribution is concerned with the long-term stress-induced deformatio n and the simultaneous fluid permeation of rock salt. To this end. a couple d finite-element strategy is presented. where the problem is formulated in the context of the theory of fluid-saturated porous media, considering two phases, i.e., the rock salt as a solid phase in which the remaining pores a re filled with brine as a fluid phase. The constitutive model for the rock salt is based on true triaxial experimental tests thus taking into account a distinct boundary between the dilatancy and the compression domains in th e octahedral stress space. For integration of this constitutive law, an imp licit integration algorithm is presented. ft is shown that the number of re sulting equations can be reduced to two, irrespective of the dimension of t he problem under investigation, and for solution of this set of equations a two-level strategy is presented. For illustrative purpose, the performance of the algorithm is demonstrated for a cylindrical specimen with two drill ings loaded in compression and fluid pressure. (C) 2001 Elsevier Science B. V. All rights reserved.