装配式地铁车站结构的接缝防水性能一直备受行业的关注，本文针对装配式车站的结构构造、构件制作及施工工艺等特点，对与接缝防水性能高度相关的“接缝张开量”和“密封垫错位量”两个关键参数的主要影响因素和控制指标进行了分析，结合密封垫防水性能试验研究及实际工程应用监测结果，充分论证了接头接缝“两垫+一注+一嵌”多道防线的关键技术，双道密封垫以三元乙丙橡胶（EPDM）弹性密封垫作为主防水，复合遇水膨胀橡胶作为加强防水，形成复合式多孔多槽形密封垫，密封垫为接缝防水主要防线，注浆和嵌缝为辅助防线。研究和实际应用表明，装配式车站结构的接缝防水，不仅在防水构造措施方面与盾构隧道不同，而且在各项控制标准方面也存在较大差异，张开量10mm、错位量5mm是装配式车站结构接缝防水性能控制的合理指标；单道防水密封垫，在张开量10mm、错位量5mm情况下，能抵抗水压力1.0MPa，满足埋深30m车站结构抵抗2~3倍水头压力的性能要求，并在使用100年后，仍存在约67%的残余应力值，具有长期耐水压性能；双道防水密封垫，较单道密封垫防水性能提高有限，提高率在20%~30%之间，但在衬砌外道密封垫出现局部漏水时，双道密封垫的优势显著；从接缝合理张拉荷载的角度考虑，三元乙丙橡胶密封垫的硬度需要较常规盾构隧道密封垫降低5SHA，即采用60SHA，其单位长度完全压缩荷载指标不大于40kN/m；从目前已建和在建的工程来看，实测车站结构接缝最大张开量和表面最大错台量均满足接缝防水性能控制标准的要求，在未设置外包防水层的情况下，接缝无渗漏水现象发生。

The joint waterproof performance of the prefabricated metro station structures has been paid much attention by the industry. In view of the characteristics of the structure, component manufacturing and construction technology of the prefabricated stations, this paper analyzes the main influence factors and control indexes of the two key parameters of "joint gap amount" and "gasket offset amount" which are highly related to the joint waterproof performance. Combined with the experimental research on the waterproof performance of the sealing gasket and the monitoring results of the actual engineering application, the key technologies of the multiple waterproof lines of “two gaskets + one injection + one embedding” of the joint’s seam have been fully demonstrated. The “two gaskets” use ethylene-propylene terpolymer (EPDM) elastic sealing gasket as the main waterproof, and the composite water swelling rubber as the reinforced waterproof, forming a composite porous sealing gasket with multi grooves. The sealing gasket is the main defense line of the joint waterproof line, and the grouting and caulking are the auxiliary defense lines. The research and practical application show that the joint waterproof of prefabricated station structures is different from that of shield tunnels not only in waterproof structural measures, but also in various control standards. The gap amount of 10mm and the offset amount of 5mm are reasonable indicators for the joint waterproof performance control for prefabricated station structures. The single waterproof sealing gasket can resist the water pressure of 1.0MPa under the condition of the gap amount as 10mm and the offset amount as 5mm, meeting the performance requirements of the station structure with 30m buried depth to resist 2-3 times of the head pressure. After 100 years of use, it still has about 67% residual stress value, and has long-term water pressure resistance performance. The double sealing gaskets have limited improvement in waterproof performance compared with the single sealing gasket, with an improvement rate of 20% ~ 30%. However, when there is local water leakage in the outer sealing gasket of the lining, the double sealing gaskets have significant advantages. From the perspective of reasonable tensile load of joints, the hardness of EPDM rubber gasket needs to be reduced by 5SHA compared with that of conventional shield tunnel, i.e., 60SHA is adopted, and the complete compression load index per unit length is not more than 40kN/m. According to the existing and under construction projects, the measured maximum gap of the joint for the station structure and the maximum offset of the surface meet the requirements of the joint waterproof performance control standard. In the case of no external waterproof layer, there is no leakage at the joint.

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北京城建集团创新项目(新型预制装配式地下车站结构模型试验研究); 国家重点研发计划(2017YFB1201104)