EFFECTS OF APPLIED STRESS ON EFFECTIVE ELASTIC-ANISOTROPY IN CRACKED SOLIDS

A physical model is developed to calculate the effective elastic moduli of a cracked solid medium under stress. The influence of applied stress on the process of opening (or closure) of various distributions of differently oriented cracks (with arbitrary aspect ratio) is used to calculate effective elastic parameters at relatively low stresses on the basis of a self-consistent approach. The results of these calculations are successfully compared both with experimental data (Nur & Simmons 1969; Rai & Hanson 1988), and with the results of an alternative phenomenological model based on the Landau-Ginzburg approach to critical phenomena. The latter also includes crack growth at higher stresses, and describes the destruction of the medium in terms of an order parameter, the value of which is determined by the minimum of a thermodynamic potential.