An associated elastic–viscoplastic constitutive model for sandstone involving shear-induced volumetric deformation

In contrast to hard rocks, weak rocks often have significant shear-induced volumetric contraction/dilation under short-term or long-term loadings, and this behavior necessitates the development of an unconventional constitutive model. As such, an elastic–viscoplastic constitutive model characterizing the mechanical behavior of weak rocks is proposed, and its validity is demonstrated by comparing the simulated and the actual deformational...