A new constitutive model for underground chemical explosions in partially saturated porous rock

ABSTRACT: A thermodynamically consistent constitutive model for partially saturated porous rock formations has been de-veloped. It is being used in numerical simulations of dynamic loading induced by chemical explosions in underground cavities embedded in nonwelded tuff formations. The proposed constitutive model was calibrated against laboratory scale mechanical tests such as uniaxial strain, triaxial compression, and constant mean stress drained and undrained conditions. These tests pro-vide insights regarding material responses to volumetric and shear deformations that may be experienced during spherical waves propagation, and after the establishment of the residual-stress state around the explosive cavity. The current model is aimed at describing a wide range of conditions encountered in rock under explosive loading conditions such as shock-compressed rock states, pressures of few gigapascals near the source, and nonlinear elastically deformed states away from the source. The proposed constitutive model is useful for a variety of applications such as cavity mining, subsurface compressed hydrogen and air storage, and nuclear waste disposals, among others.