Numerical analysis of DRC segment under inner water pressure based on full-scale test verification for shield tunnel

• An effective 3D finite element model for DRC segment is proposed and it could simulate the mechanical behaviors of DRC segment quite well.
• Crack pattern, relative slip, contact stress and strain distributions, and the relation of deflection and load of DRC segment under combined loads are investigated by finite element method.
• Contact analysis with various friction coefficients is applied to indicate the relative slip at interface between concrete infill and the ductile cast iron segment for DRC segment.
• The three sources of nonlinearity: material, geometrical and boundary contact are all taken into consideration in the modeling.

Shield tunnel subjected to high inner water pressure is used to prevent waterlogging, and DRC (Ductile cast iron segment and Reinforced Concrete) segment has been developed for obtaining high loading capacity in the linings of underground drain shield tunnel. In general, tunnel linings resist bending moment, hoop and shear forces. Cracks will occur in tunnel linings under high inner water pressure during operating period, while tensile stress will appear at member section. On the basis of the existing experimental results, the crack pattern, relative slip, contact stress, strain distribution, and relationship between deflection and load of DRC segment were investigated by finite element method. A three-dimensional finite element model of DRC segment was proposed to simulate its nonlinear behaviors by applying MSC.Marc software package. Taking the three sources of nonlinearity into account, the proposed numerical model fully presented the complicated behaviors of DRC segment during the whole loading process. Results indicated that the numerical studies agreed well with the experimental tests, and comparisons between them demonstrated that the proposed numerical model could excellently analyze the nonlinear behaviors of DRC segment under combined hoop and bending loads.