Abstract:  A largediameter (15 m) highway shield tunnel for drainage and storage with superdeep cover depth (10 m) requires high joint bearing capacity under high internal water pressure. Thus, a new circumferential fast connector is developed. The fast connector assembly time is short and does not require manual tightening, the roundness of the tunnel is high after assembly, the segment dislocation and opening are small, and waterproof performance is good. In this paper, to investigate the structural form, material properties, the connection between the connector and anchor bar, and the force transmission between the connection and concrete segment, a case study is conducted on a 650 mm thick segment, a tensile physical test of the joint is implemented, and a numerical simulation method is employed to compare experimental and calculated values. The main conclusions are summarized as follows: (1) The tested cast iron connection load capacity is 512 kN, which satisfies design requirements. The bearing capacity during the elastic phase is 400 kN, and the ultimate bearing capacity is 645 kN, which can guide shield tunnel design. (2) The experiments conclude with connector failure; thus, the design of the connection between the anchor bar and connector is reasonable and reliable. When the test is suspended, the maximum stress of the four anchor bars is 348 MPa, reaching 87% of the tensile yield strength of HRB400 anchor bars, which is close to the design value of 360 MPa. (3) Under axial tensile force, the stress of the connector body and anchor is uneven; thus, the unevenness should be considered in the connection design, and a reasonable optimization design should be realized.

Key words:  , shield tunnel, fast connector, tensile experiment, anchor mechanical performance