APPLICATION OF FRACTURE-DAMAGE MODEL TO ANCHORAGE OF DISCONTINUOUS JOINTED ROCKMASS OF EXCAVATION AND SUPPORTING
加锚断续节理岩体断裂损伤模型在硐室开挖与支护中的应用

According to the theories of fracture mechanics and damage mechanics, the constitutive model and fracture damage mechanism of brittle discontinuous jointed rockmass are systematically studied under the state of complex stresses. Firstly, with the equivalent strain energy, the constitutive relation of anchored brittle discontinuous jointed rockmass is derived under compression-shear stresses. The constitutive relation under tension-shear is also developed according to the theory of self-consistence. Secondly, the damage evolution equations of discontinuous multi-crack rockmass under compression-shear and tension-shear are put forward according to the wing crack-initiating criterion. Finally, based on the above constitutive models and the damage evolution equations, the three-dimensional finite element procedures have been developed to model the ground movements that occur when underground power-houses of Langyashan Pumped-storage Power Station are installed in discontinuous jointed rockmass. The anchor supporting is an important component of this underground powerhouses excavation works. Besides the displacement fields and the secondary state of stresses induced by excavation disturbance, the effects of anchorage and the damage evolution around the power-houses have been particularly described during the processes of installation. The obtained numerical results are compared with the in-situ monitoring ones in order to verify the validity of the proposed models and equations. Some useful conclusions are drawn and they have great significances to the project.