Analytical solution of a circular lined tunnel with alterable mechanical property under hydrostatic stress and internal pressure

The influence of the interaction between surrounding rock and lining on the long-term behaviour of a tunnel in service is significant. In this paper, we proposed a mechanical model of the circular lined tunnel with the alterable mechanical property under hydrostatic stress and radially inner surface pressure of the lining. The alterable mechanical properties of the surrounding rock and the lining are embodied by the changing of their elasticity modulus with service time and radial direction of the tunnel, respectively. The proposed mechanical model is successfully validated by comparison with the existing theoretical models and the numerical simulation, respectively. The influences of the main parameters of the proposed mechanical model, such as the radial power-law indexes and the time-varying coefficients of the surrounding rock and the lining, as well as the radially inner surface pressure of the lining, on the interface displacement and pressure between surrounding rock and lining are investigated. The research results can provide some valuable references for timely diagnosis and correct evaluation of the long-term behaviours of a tunnel in service.