The permeability of rock mass is closely related to the stability and safety of underground structure, especially in underground water-sealed storage caverns. With regard to the estimation approaches in predicting the hydraulic conductivity of fractured granite in water-sealed storage caverns, there are some limitations of parameter selection leading to poor applicability. Focusing on the contribution of the water conduction fractures (WCF) to the hydraulic conductivity, we attempted to propose a novel model, the CA model, for estimating its hydraulic conductivity based on the fracture orientation index and the normal stress index by analyzing the borehole wall imaging results and borehole water-pressure test results in the site of underground water-sealed storage caverns. The results indicated that the proposed model is suitable for low-permeability and unfilled fractured granite, exhibiting good effectiveness by clarifying the relation between geomechanical parameters and hydraulic behavior. Further, the parameters upon which the proposed model is based are representative and easy to obtain, which has certain guiding significance and reference value for analyzing the permeability characteristics of similar rock masses.

中文翻译：

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地下水封蓄水洞室低渗透未充填断裂花岗岩导水率估算模型

岩体的渗透性与地下结构的稳定性和安全性密切相关，尤其是在地下水封库洞中。对于预测水封库洞中裂隙花岗岩导水率的估算方法，由于参数选择存在一定的局限性，适用性较差。针对导水裂缝（WCF）对导水率的贡献，我们尝试提出一种新的模型，CA模型，通过分析井壁，基于裂缝取向指数和法向应力指数估计其导水率地下水封库洞现场成像结果和钻孔水压测试结果。结果表明，该模型适用于低渗透率和未充填的裂缝性花岗岩，通过阐明地质力学参数与水力行为之间的关系表现出良好的有效性。此外，该模型所依据的参数具有代表性且易于获取，对分析类似岩体的渗透特性具有一定的指导意义和参考价值。