Experiment on mechanical properties of steel and concrete composite segment for shield tunnel

Targeting at the mechanical properties of steel and concrete composite segment for shield tunnel, 4 groups of model tests on steel and concrete composite segment under pure bending loading were added on the basis of existing 10 groups of tests and previous research results. The impacts of the thickness change of steel plates, headed shear studs and joint plates on the carrying capacity and deflection of composite segment were further studied, and the results from the new tests were compared with those existing results. Meanwhile, according to previous researches, a bilinear method was proposed to determine the yield load of composite segment. The results show that a) the thickness of skin plate has the most significant impact on the deflection and carrying capacity of composite segment; b) shear studs can effectively restrict the deformation of composite segment and improve its carrying capacity; c) joint plates acting as shear studs markedly improve the carrying capacity of composite segment without shear studs but don't affect the carrying capacity of which with shear studs. Finally, from the perspective of the newly added influencing factors on mechanical properties, the strain distribution laws along width and height direction of the composite segment in new tests and existing tests were analyzed and replenished. The testing results of the 14 groups give a comprehensive insight into the mechanism of steel and concrete composite segment for shield tunnel.