Modeling the behavior of compacted bentonites under low porosity conditions: Fid-Bau Portal

Modeling the behavior of compacted bentonites under low porosity conditions

Navarro, Vicente / De la Morena, Gema / Gharbieh, Heidar / González-Arteaga, Jesús / Alonso, Juan / Pulkkanen, Veli-Matti / Asensio, Laura

Abstract

Abstract This article proposes an approach to ensure consistency between constitutive formulations used in double-porosity models when the macrostructural void ratio, e M, is very small. These formulations model processes of different physical natures and therefore are usually presented independently, in which case an additive decomposition is assumed, and they calculate the total strain of the system as the sum of the strains caused by each process. This independence means that when e M is reduced, the contributions considered are not always consistent. To solve this problem, soil stiffness in the proposed approach is increased when e M is reduced, and at the same time the effect on strain by macrostructural processes not linked to changes in stress is reduced. To simulate the flow, it is assumed that there is always a minimum operating value of e M that controls mass transport. This approach was applied to a practical case, and confirmed that when the effect of the stress state on microstructure behavior was taken into account, the conceptual framework initially proposed for non-negligible e M values was satisfactorily extended.

Highlights • Double porosity models when the macrostructural void ratio is very small are analyzed. • The independent additive decomposition of strains may cause inconsistencies. • An increment of the stiffness of soil is proposed when de macro void ratio is reduced. • A minimum operative value of the macro void ratio is considered to control the flow. • The approach was proven valid when the stress state on microstructure is considered.