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

APPLICATION OF FRACTURE-DAMAGE MODEL TO ANCHORAGE OF DISCONTINUOUS JOINTED ROCKMASS OF EXCAVATION AND SUPPORTING

应用断裂力学与损伤力学理论,对复杂应力状态下脆性断续节理岩体的本构模型及其断裂损伤机制进行研究。根据应变能等效的方法和自洽理论,建立加锚断续节理岩体在压剪、拉剪应力状态下的断裂损伤本构模型;且建立裂纹在压剪和拉剪状态下的损伤演化方程。基于以上的本构模型和损伤演化方程,编制三维有限元程序,并将其应用于琅琊山抽水蓄能电站地下厂房硐室开挖与支护工程的稳定性分析中,研究地下厂房硐室在开挖支护过程中的稳定性。重点分析硐室围岩在开挖过程中的应力状态、变形特性及损伤演化过程。将计算所得出的硐室开挖边界附近的位移值与原型观测值进行比较,得出一些对工程有指导意义的结论。

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.