盾构隧道环向快速连接件力学性能试验研究

15 m级的大直径公路盾构隧道与10 m级超深覆土高内水压作用下的排水调蓄盾构隧洞对接头有高承载力的要求，为此开发新型环向快速连接件。该连接件具有拼装时间短、无需人工拧紧、拼装完成后的隧道真圆度高、管片错台与张开量小、防水性能高的优点。为研究连接件的结构形式、材料性能、连接件与锚筋之间的连接、连接件与混凝土管片之间力的传递，以650 mm厚的管片为原型，开展接头抗拉物理试验，并采用数值模拟的方法实现试验值与计算值的对比分析。主要结论如下： 1）本次试验所采用的铸铁连接件屈服承载能力为512 kN，满足试验指标要求。弹性阶段的承载力为400 kN，极限承载力为645 kN，可以应用于指导盾构隧道的设计。2）试验破坏发生在连接件本体部位，锚筋与连接件之间的连接设计合理可靠。试验终止时，4根锚筋的最大应力值为348 MPa，达到HRB400锚筋抗拉屈服强度的87%，接近其抗拉强度设计值360 MPa。3）连接件在轴心拉力作用下，其本体与锚筋的受力是不均匀的，在连接件设计中应考虑这种不均匀性，进行合理的优化设计。

Mechanical Performance and Experimental Research on Circumferential Fast Connector of Shield Tunnel

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.