Numerical study of shear band formation in triaxial compression tests

Abstract

Numerical simulations of triaxial compression tests are performed in order to investigate the applicability of the material point method (MPM) to large-deformation geotechnical problems. A Mohr-Coulomb constitutive model is adopted as a geotechnical nonlinearity, for which parameters are obtained by experimental results. The stress-strain relationships obtained in the simulations show good agreement with the experiments at high levels of strain, thus demonstrating the effectiveness of MPM. Parametric studies are also performed in order to investigate factors that influence the relationship between the initial and final shear bands observed during simulations of triaxial compression tests. The main findings of the study are followings: (1) initial shear bands are generated near the constrained edges of a specimen; (2) when both top and bottom edges of a specimen are constrained, initial shear bands near the edges at which the external forces are applied develop finally into clear shear bands; (3) specimen geometry has a major influence on the formation of shear bands in the case of rectangular specimens.

Extended B‐spline‐based implicit material point method enhanced by F‐bar projection method to suppress pressure oscillation

“…Thus, the MPM has been developed mainly for dynamic analyses of ground structures subjected to dead weight 13,14 . Although the imposition of nonhomogeneous boundary conditions can be realized by embedding other media into the continuum body, 24,25 it is difficult to handle more complex problems involving various types of boundary conditions in this way. Since the challenge explained above is widely encountered in mesh‐free methods, 26‐28 several approaches, such as the penalty method, the method of Lagrange multiplier and Nitsche's method, 29 have been studied for imposing Dirichlet boundary conditions, and these approaches have been applied to MPM frameworks 30‐32 .…”