Numerical simulation of triaxial compression test for brittle rock sample using a modified constitutive law considering degradation and dilation behavior

Abstract

The understanding of the rock deformation and failure process and the development of appropriate constitutive models are the basis for solving problems in rock engineering. In order to investigate progressive failure behavior in brittle rocks, a modified constitutive model was developed which follows the principles of the continuum damage mechanics method. It incorporates non-linear Hoek-Brown failure criterion, confining pressure-dependent strength degradation and volume dilation laws, and is able to represent the nonlinear degradation and dilation behaviors of brittle rocks in the post-failure region. A series of triaxial compression tests were carried out on Eibenstock (Germany) granite samples. Based on a lab data fitting procedure, a consistent parameter set for the modified constitutive model was deduced and implemented into the numerical code FLAC^3D. The good agreement between numerical and laboratory results indicates that the modified constitutive law is well suited to represent the nonlinear mechanical behavior of brittle rock especially in the post-failure region.

Keywords

progress failure / strength degradation / dilation / Hoek-Brown criterion / numerical simulation / brittle rock

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