Experimental investigation on the triaxial unloading mechanical characteristics of sandstone immersed in different brines

Abstract In this study, the stress–strain curves of sandstone soaked in 5% NaCl and K 2 SO 4 solutions under different loading unloading paths were obtained by carrying out confining pressure tests on specimens. Thereafter, strength, deformation, failure characteristics specimens analysed. First, capacity was found to be greater than those , amount increased order increasing axial < constant deviatoric stress pressure. When pressure, strain change rate that specimen NaCl, had following trend: adding > The deformation modulus Poisson's ratio during exhibited an exponential with ratio. Poisson’s period respectively less . Second, total energy absorbed always paths. effect immersing solution acoustic emission unclear. Compared dry specimens, brine lower mineral composition higher, clay content. contents plagioclase calcite similar sandstone, but no or detected