On the Dynamic Soil Behavior under Triaxial and Simple Shear Modes

Abstract

Although much has been discussed on the liquefaction phenomenon and cyclic behavior of saturated sands, relatively little has been clarified on the difference between their cyclic behavior under simple and triaxial shear modes, particularly under strain-controlled conditions. Thus, in this study, comparative cyclic strain-controlled simple (DSS and TxSS) and triaxial (CTX) shear tests were performed on reconstituted specimens of Baie-Saint-Paul and Ottawa C-109 sands. To indicate further investigation into the cyclic behavior under triaxial and simple shear modes, the CTX and TxSS tests were numerically simulated using a proposed energy-based pore-water pressure model through the FLAC3D platform. The outcomes of the numerical simulations were presented in terms of the stress–strain hysteresis loop and the distribution of the dissipated energy and excess pore-water pressure generation within each element of CTX and TxSS soil specimens. Unlike TxSS soil models that experience a relatively uniform stress state, the numerical simulation revealed the nonuniformity of the produced stress–strain and pore-water pressure within triaxial specimens. The comparative cyclic strain-controlled test results revealed that the DSS and TxSS specimens liquefy slower than triaxial specimens, in contrast to cyclic stress-controlled results found in the literature.