Correlating permeability coefficients of fractured rock mass in unidirectional and radial flow Configurations: Method and Application

• A calculation equation of radial flow permeability coefficient tensor was proposed. • A correlation between the permeability coefficient of unidirectional flow and radial flow was established. • The influence of different flow configurations on the water inflow of the cavern was analyzed. • The calculation method of water inflow in cavern under different flow configurations was discussed. Groundwater flow configurations typically include unidirectional and radial flow and the flow field in rock mass are usually influenced by the flow configuration obviously. In this study, a calculation equation of radial flow permeability coefficient tensor was proposed, based on the calculation method of unidirectional flow permeability coefficient tensor and the correlation between rectangular and cylindrical coordinate systems. A correlation between unidirectional and radial flow permeability coefficient was established based on Darcy’s law, the equivalent permeability coefficient equation under radial flow, and the correlation of equivalent hydraulic aperture between unidirectional and radial flow. The core for the correlation was the relation of hydraulic apertures in terms of the fracture roughnesses in the two flow configurations. For an underground water-sealed storage cavern, the permeability coefficients of different flow configurations in the engineering zone were determined, and the numerical simulation of water inflow was carried out. The results indicated that the permeability coefficient of unidirectional flow was greater than that of radial flow. Water inflow with permeability coefficient partition assignment based on the flow configuration was higher than that with entire radial flow permeability coefficient. In addition, a calculation method of the water inflow into cavern considering permeability coefficient partition was established and verified by the numerical simulation.