Mechanical Analysis of Circular Hydraulic Tunnel with Double Linings.

Through the complex function method, an analytical method for solving the circular hydraulic tunnel with double lining is proposed. The established model is based on the interaction between the surrounding rock and the primary lining, the primary lining and the secondary lining (full contact), taking internal water pressure and the support delay into account. Based on the preset boundary conditions, the equations for solving the coefficients of the relevant analytic functions can be established, and then the obtained analytical function can be used, the stress components of any point in the surrounding rock, the primary lining and the secondary lining can be solved. By comparing the numerical solution, it is found that the analytical method proposed is correct and effective. At last, the parameters are analyzed from three aspects of controlling the water pressure in the hydraulic tunnel, exchanging the elastic modulus of linings and controlling the thickness of linings, and the factors and results affecting the stress distribution of lining are discussed. The load transfer mechanism and law of the double-lined hydraulic tunnel are revealed, which provides a theoretical basis for the preliminary design and construction of the lining protection project. [ABSTRACT FROM AUTHOR]