中文摘要：

地下水封洞库的围岩是一种低渗透岩石,其气体渗透特性,以及气体渗透率随压力的变化是地下水封洞库工程非常关注的问题。该文对某石油储备地下水封洞库的风化花岗片麻岩进行了室内的气体渗透特性试验,滑脱效应试验以及扫描电镜试验。试验结果表明：该风化花岗片麻岩气体渗透在不同围压阶段,渗透率和孔隙度变化规律不同;存在一个围压拐点,小于拐点值时,渗透率随围压满足指数函数,大于拐点值时,满足二次函数关系;SEM试验表明,岩石内部不整合接触形成的微裂隙和微孔洞导致了围压加载过程中渗透率和孔隙度不同变化规律;气体在低渗透岩样渗流过程中存在滑脱效应,应对测试所得到的渗透率进行滑脱效应的修正;对于地下水封洞库,设计和运行时要考虑气体渗透的滑脱效应的影响;气体滑脱效应的影响与围压有关,当围压为8 MPa--9 MPa时,气体滑脱效应对气测渗透率影响最大。

英文摘要：

The rock surrounding an underground water-sealed cave is a kind of low permeability medium, its gas permeability property and the change in gas permeability when subjected to different confining pressures draw considerable attention in the construction of underground water-sealed caves. This paper conducts experiments on gas permeability and gas slippage effects, and uses a scanning electron microscope （SEM） to study the weathered granitic gneiss of an underground water-sealed cave in China. The results show that the laws governing the change in gas permeability and rock porosity vary at different stages of confining pressure. It is found that there is a threshold point for confining pressure. The relationship between gas permeability and confining pressure is exponential when the pressure is larger than the value, otherwise, it is a quadratic function relationship. The SEM tests indicate that the different behaviors of gas permeability and porosity are caused by the micro-fissures and micro-void generated by unconformable contact when pressure is applied. Additionally, the measured values of gas permeability need to be modified due to the existence of gas slippage effects, and these must be taken into account when designing and running underground water-sealed caves. Gas slippage is closely related to confining pressure and its maximum impact occurs at a confining pressure of 8 MPa-9 MPa for this weathered granitic gneiss.