Study on Rockmass Deterioration Model Based on the Unified Strength Theory

Abstract

Strain softening model;Unified strength theory;Rockmass deterioration model;FLAC3D Abstract:Aiming at the problem that traditional elasto-plastic constitutive models have not been successful in predicting the depth and extent of brittle failed of hard rocks under high geo-stress condition, a new rockmass deterioration model(RDM) based on the unified strength theory is put forward in the basis of strain softening model and cohesion weaking and friction strengthening (CWFS)model. In the new model, the influence of intermediatemain stress to characteristic of rockmechanics is considered. Based on the method of lagrangian finite difference, a finite difference format of unified strain- softening elastoplastic model with strength parameters of c and φ is established. The constitutive unified elastoplastic model is imported into FLAC3D using a dynamic-link library file developed by VC++.Based on the new model, the traditional triaxial tests (with different confining pressure) and true triaxial tests (with intermediate principal stress ratio) are simulated in FLAC3D, and the measured data are compared with the results that are are simulated by strain softening model and CWFS model. The analytic results suggest that the rockmass deterioration model based on the twin shear unified strength theory has more strong applicability