Karst Aquifer Water Inflow into Tunnels: An Analytical Solution

Figure 2

Relationships between lining structures. , , and are pressure heads along the joints of the grouting circle and initial support circumference, the initial support and secondary lining circumference, and the secondary lining inner circumference, respectively. , , and are radii of the grouting circle, initial support, and internal of the secondary lining, respectively. , , and are permeability coefficients of the grouting circle, initial support, and secondary lining, respectively.