Nonlinear analysis of tunnels in clayey/sandy soil with a concrete lining

In the nonlinear analysis of tunnels embedded in clayey or sandy soil with concrete lining, nonlinearity arises due to three parameters. The first parameter is the nonlinear material behavior of the lining and the surrounding soil. The second parameter is a result of the large deformations effect. The third parameter is the nonlinear nature of the contact between the concrete lining and the surrounding soil (essentially the slippage between the two materials). In this paper the three parameters of nonlinearity are modeled and implemented in a finite element program.