Constitutive Model Of Rock - Like Materials Considering Damage And Residual Strength And Its Application

Making use of the damage mechanics theory and the statistical strength theory and taking Hoek-Brown criterion as the distribution variable, a three-dimensional damage constitutive model reflecting the whole process of rock fracture is established under triaxial stress state based on the improved Harris distribution. Through modifying the expression of Hoek-Brown criterion by the Hooke’s law, the uniaxial damage constitutive model is established based on the uniaxial compression experiments and the damage statistical strength theory. The similarity of mechanical behaviours between tension and compression tests is investigated and discussed, and the constitutive model under uniaxial tensile loading is proposed which could be used to explain failure behaviour of uniaxial tension of rock. In this dissertation, damage coefficient J,which can reflect the progressive failure and the properties of the rock to a certain degree, is proposed by analyzing the shortage of the existing research results.A new quantitative geological strength index (GSI) rock mass classification system based on the two major controlling factors-the joint condition factor JC and the block volume Vb. Combined with the new Hoek-Brown strength criterion, it can estimate the jointed rock mass strength and the rock mass deformation parameters. Considering certain regions of Beishan, Gansu Province, in this research, the peak GSI adjust to the residual GSIr by means of using the GSI quantitative evaluation method. Finally, the residual strength and the mechanical parameters of jointed rock mass in these areas are calculated successfully.In this dissertation, the USDFLD subroutine is completed on the basis of FORTRAN language, which can obtain materials integration point data and redefine the minimum principal stress σ3 as field variables, and then the stress-strain relations are changed with the confining pressures. Taking advantage of ABAQUS, the model units of rock mechanics test are analyzed by the finite element method. Eventually, combined with the rock mass mechanical parameters which are determined by quantitative GSI system, it is seen that the successful application of programmed damage constitutive model is realized through the simulation analysis of the deep rock mass engineering examples, which has certain guiding significances for geotechnical problems.