Abstract:

The longitudinal stiffness of shield tunnel structure is regarded to be unchanged in present longitudinal design methods. As a result, the coordination of longitudinal deformation and force of the longitudinal structure of the shield tunnel can not be achieved; and the longitudinal optimal design of the structure can not be realized. Therefore, a new shield tunnel design model is proposed based on the study of traditional longitudinal equivalent continuous model. The model is named nonuniform stiffness longitudinal equivalent continuous model. The inhomogeneity of longitudinal stiffness of shield tunnel can be achieved by the model, and reference can be provided for coordination of longitudinal deformation and force of the longitudinal structure of the shield tunnel. Two optimal models, one with deformation as target and force as sanction and the other one with force as target and deformation as sanction, are established based on the equivalent longitudinal model. The feasibility of the models is verified by analyzing shield tunneling in weakandsoft interlayer. In addition, the longitudinal stiffness distribution of the tunnel structure can be obtained by using the optimized results; and value scope of the coordination of longitudinal deformation and force of the longitudinal structure of the shield tunnel can be obtained.

Key words: shield tunnel, longitudinal design, optimal design, penalty functional method