PBA工法装配式地铁车站结构设计关键技术研究

Research on key technology of PBA method assembly subway station

PBA工法为修建地铁车站的常用方法,存在工序复杂、施工周期长和作业环境恶劣等问题。因此提出装配式地铁车站方案,得到适用于PBA工法的地铁车站二次衬砌结构分块方案和兼顾预制衬砌装配的安装工序。通过数值模拟建立车站结构的“梁-弹簧”模型,对比不同衬砌厚度、转动刚度的现浇与装配式车站受力变形差异,得到PBA地铁车站的装配式优化方案。计算结果表明:扣拱及边墙厚度为0.8m、底板厚度1m时,装配式车站结构受力变形情况与现浇式车站最接近;在对转动刚度与结构受力变形关系的研究中发现,当转动刚度达到5×10^(5)kN·m/rad后装配式车站结构受力和变形基本稳定;对比同一厚度下装配式车站结构与现浇式车站结构的受力变形,发现转动刚度取值为5×10^(5)kN·m/rad时装配式车站结构底板弯矩及变形小于现浇式车站,弯矩最大减幅达到36.3%,变形最大减幅达到10.8%,说明适宜的转动刚度可以有效优化装配式车站结构底板处的受力变形特性;综合考虑车站个部位预制衬砌载荷情况,确定了车站各部位预制衬砌的配筋及接头尺寸。对比传统PBA工法,装配式地铁车站PBA工法提高了施工效率、车站结构受力变形性能,节约了成本。

As a common method for building subway stations,the PBA method has problems such as complex process,long construction period and poor working environment.Therefore,the scheme of prefabricated subway station is proposed,and the block scheme of secondary lining structure of subway station suitable for PBA method and the installation process of prefabricated lining assembly are obtained.The“beam-spring”model of the station structure is established by numerical simulation.The difference of stress and deformation between cast-in-place and assembled station with different lining thickness and rotational stiffness is compared,and the assembly optimization scheme of PBA subway station is obtained.The calculation results show that:When the thickness of arch and side wall is 0.8m and the thickness of bottom plate is 1m,the deformation of assembled station structure is the closest to that of cast-in-place station.In the study of the relationship between rotational stiffness and structural stress and deformation,it is found that when the rotational stiffness reaches 5×10^(5)kN·m/rad,the stress and deformation of the fabricated station structure are basically stable.The stress and deformation of the fabricated station structure and the cast-in-situ station structure under the same thickness are compared.It is found that the bending moment of the bottom plate of the fabricated station structure is smaller than that of the cast-in-situ station structure when the rotational stiffness is 5×10^(5)kN·m/rad,and the maximum reduction reaches 36.3%,maximum deformation reduction of 10.8%.It shows that the appropriate rotational stiffness can effectively optimize the deformation characteristics of the floor of the fabricated station structure.Considering the load of precast lining in each part of the station,the reinforcement and joint size of precast lining in each part of the station are determined.Compared with the traditional PBA method,the PBA method of the assembled subway station improves the construction efficiency,the deformation performance of the station structure and saves the cost.