Static Deformation of Rock

The nonlinear deformation of rock and the hysteresis in stress-strain curves carried through a complete loading-unloading cycle is shown to be due to the cracks which are found in most samples. Theoretical analysis of models in which pores and cracks are assumed to be dispersed throughout an elastic matrix leads to general expressions for the elastic parameters. These expressions are evaluated after first specifying the shape of each cavity and applying one of several techniques for including the effect of interaction between adjacent cavities. The differential scheme and Mackenzie's variation on the self-consistent approximation are found to reproduce the observed values for compressibility of porous glass most satisfactorily.