Study of adjacent construction of two tube shield tunnels by centrifugal model test

The adjacent construction of two tube shield tunnels was simulated by centrifugal model test method.The value and the distribution regularities of structural transversal internal forces and their variation with advanced distance of shield machine and the relative positions of two tunnels were studied.The results showed that the inside of top and bottom of lining structure subjected to tension,while the outside of left and right hance subjected to tension;and the largest bending moment occurred on the arch bottom. The whole structure was compressed;and the smaller axial force occurred on the arch crown and arch bottom,while the bigger occurred on the left and right hance.The distribution of structural internal force was symmetrical after the construction of the first tunnel;and the structural internal force of two tunnels changed with their relative position when the second tunnel was constructed. The new tunnel construction had obvious influence on the structural internal force of the existed tunnel;and the corresponding strengthening measures should be taken in the design and construction.