新型装配式衬砌在矿山法施工铁路隧道中的应用研究

为解决矿山法施工铁路隧道二次衬砌拱顶易出现的空洞、厚度不足、裂缝、掉块等病害，以重庆铁路枢纽东环线胡家沟隧道为依托，采用拱部预制衬砌替换现浇衬砌的方法，研究拱部衬砌预制工艺、高精度悬臂侧墙施工工艺、拱部预制衬砌运输及拼装施工工艺和拼装配套设备，并阐述装配式衬砌在施工中需重点解决的技术难题及对策，如采用高精度衬砌模板台车解决接头直线度的问题、采用全环通长定位筋解决悬臂侧墙钢筋骨架稳固的问题等，形成一套完整的新型装配式衬砌拼装技术。经现场应用表明： 1）采用“拱部预制衬砌+侧墙现浇”的装配式衬砌施工技术是可行的，可以有效解决矿山法施工隧道拱部质量缺陷问题，提高拱部衬砌质量； 2）新型装配式衬砌采用“L”型榫接头及大球形接头，大球形接头较“L”型榫接头更易控制施工质量，更易于拼装； 3）通过采用拱部预制衬砌高精度定制钢模、高精度悬臂模板台车、悬臂侧墙在混凝土浇筑过程中进行二次精调等关键技术，保证了接头施工精度，满足了拼装要求； 4）通过分析衬砌结构受力变形监测数据，得出隧道衬砌结构内力的受力变形规律； 5）新型装配式衬砌施工技术机械化程度高，施工过程中结构稳定可靠，安全性较高。

Application of New Prefabricated Lining Structure in Railway Tunnel Construction by Mining Method

Secondary lining crowns of railway tunnels constructed by the mining method have many defects, such as hollows, insufficient thickness, cracks, and falling blocks. Accordingly, a case study is conducted on the Hujiagou tunnel of the east ring line of Chongqing railway hub, and the cast in place lining is replaced by a prefabricated one. Furthermore, arch lining prefabrication, sidewall construction using a high precision cantilever, prefabricated lining transportation, and prefabricated lining assembly equipment are studied. Moreover, technical issues faced in prefabricated lining construction, including the joint straightness adjusted by high precision lining formwork jumbo and sidewall cantilever steel skeleton stabilized by entire ring universal length positioning reinforcement, are resolved, forming a complete set of new prefabricated lining assembly technology. The field application reveals the following: (1) The prefabricated lining construction technology of the prefabricated arch lining + cast in place sidewall is feasible, which can effectively avoid the quality defects of tunnel arch constructed by the mining method and improve the quality of tunnel arch lining. (2) The new prefabricated lining adopts the L type and large spherical joints, and the construction quality is easier to control and assemble by the large spherical joint than the L type joint. (3) A series of techniques, such as specially made steel mold with high precision, high precision cantilever formwork trolley, and secondary refined adjustment of sidewall cantilever during concrete casting, are adopted to ensure the joint construction accuracy and meet assembly requirements. (4) By analyzing the data monitored for stress and deformation of the lining structure, the stress and deformation law of internal force of tunnel lining structure is obtained. (5) The new prefabricated lining construction technology has a high mechanization degree, which can guarantee the stability and safety of the structure during construction.