水工隧洞衬砌水压致裂过程的渗流–损伤–应力耦合分析

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

基于弹性损伤理论和线弹性断裂力学理论,建立水工隧洞衬砌水压致裂过程中的渗流–损伤–应力耦合模型。模型采用增量变弹性损伤刚度有限元迭代法,在内水荷载逐级施加的过程中考虑损伤对于渗流的影响,可以较好地模拟在水工隧洞充水加压过程中,混凝土衬砌在应力场和渗流场耦合情况下的损伤演化及裂纹的产生、扩展的过程。工程算例结果表明:计算结果较为合理地反映高内水压力下水工隧洞衬砌的开裂规律。当水压致裂过程采用耦合模型时,衬砌的损伤演化和开裂对衬砌渗流场的影响不可忽略;由于内水外渗的的影响,衬砌的受力条件在一定程度上得到改善。

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.