SEEPAGE-DAMAGE-STRESS COUPLING ANALYSIS OF HYDRAULIC TUNNEL LINING IN HYDRAULIC FRACTURING PROCESS

Based on the elastic damage theory and linear-elastic fracture mechanic theory,seepage-damage-stress coupling model for hydraulic tunnel lining in hydraulic fracturing process is established. The finite element iteration method with incrementally variable elastic damage stiffness is applied and the influence of damage on the seepage during the process of inner water pressure gradually increasing is considered in the model. It can be better to simulate the damage evolution and the fracture formation and propagation process of hydraulic tunnel lining in the process of filling the hydraulic tunnel by the pressure water,in the coupling circumstance of stress and seepage field. The project example calculation results show that the calculation results can reasonably reflect the cracking rule of hydraulic tunnel lining under high inner water pressure. When the coupling model is applied,the influence of damage evolution and crack propagation of the lining on the seepage field can not be ignored. Moreover, because of the influence of inner water exosmosis,the force bearing condition of the lining,to a certain degree, will also be improved.