Abstract: The present study aims to investigate the mechanical properties of the circumferential joint of water conveyance shield tunnel at the Sanmen nuclear power plant(phase Ⅱ). For this, radial and tangential shear tests are conducted. In order to examine the shear properties of circumferential joints under various residual loads, the radial shear test is conducted under the ideal assembling condition and the concave and convex tenon connection condition. In comparison, the tangential shear test is conducted only under the ideal assembling condition. The results of the research reveal the following: (1) Under ideal assembling condition, the shear force is first borne by static friction and then by friction and tenon. Under the concave and convex tenon connection condition, the shear force is borne by friction and tenon. (2) The static friction, bolt, and tenon concrete act in succession in the tangential shear test. (3) The radial shear stiffness ranges from 4.67×108 to 1.42×109 N/m, and the tangential shear stiffness ranges from 4.23×108 to 8.43×108 N/m before dislocation of circumferential joints. (4) The larger is the longitudinal force, the higher is shear stiffness.

Key words: water conveyance shield tunnel, circumferential joint of segment, shear mechanism, fullscale test