Three-dimensional orthotropic equivalent modelling method of large-scale circular jointed lining

Due to the large spatial scale differences between the structure details and the global tunnel, the large-scale shield tunnels were usually modeled as continuous ‘pipes’ in the 3-D numerical analyses. The details (e.g. joints) that greatly affect the integral stiffness of the continuous 3-D tunnel models have seldom been discussed in literatures. This paper presents an idea of orthotropic equivalence for the modeling of the large-scale circular shield tunnel and the optimization procedure for the identification of the nominal material constants. Considering the tunnel’s structural characteristic in its radial, circumferential and axial directions and its periodicity, the segmentally erected lining is equivalently modeled as an orthotropic continuous structure. An optimization procedure based on the idea of inverse analysis and FE method which can quickly identify the equivalent constants is also proposed. Validation example shows that a reasonable consistency between results predicted by the equivalent/segmental models and the analytical formulas is achieved.