Abstract: The working state of the grouted mortise-tenon joints with significant bearing capacity is a crucial component in the design of dry-connection prefabricated station structures. The authors analyze the bearing capacity margin of various grouted mortise-tenon joints and propose a classification rule for the joint design criteria based on the results of the 1∶1 prototype loading test on various joints along the primary stress directions. It is suggested that the second inflection point in the joint bearing characteristic curve should be used as the limit value for the design verification of the working bending moment of the joint structure. Subsequently, the rationality of such a design criterion inflection point is validated in terms of joint deformation, joint rotation, and bending stiffness. On this basis, an envelope diagram of the bearing capacity criterion for double-tenon joints with the pretensioned steel bars on the tension side is established. The finite element numerical simulations and field test results of the same joints in practical applications are verified. The numerical calculation and the field test results indicate that the studied joints exhibit a large safety margin.

Key words: metro station; prefabrication and assembly, grouted mortise-tenon joint, bearing capacity, design criterion