隧道装配式仰拱施工荷载受力特征试验研究

Experimental Study on the Load Characteristics of Prefabricated Inverted Arch Construction in Tunnels

研究目的:相比传统现浇混凝土结构,装配式结构具有标准化程度高、施工方便、现场占地小、机械化程度高、绿色环保等诸多优点。矿山法隧道采用装配式仰拱时,除考虑运营期受力工况外还要考虑施工期受力工况,为此需要在施工机具、拼装机等作用下对结构受力情况进行研究。本文以单线铁路隧道为工程背景,通过足尺试验研究预制仰拱块在施工荷载作用下的相关受力特征。研究结论:(1)当仰拱预制块单孔纵向拉紧力达到373 kN(37.3 t)时,环向缝最小处可闭合;(2)拉紧效果与拉紧顺序和拉紧方式有关,恰当的拉紧方式可改善拉紧效果;(3)在整个施工荷载作用过程中,仰拱预制块的钢筋和混凝土均处于受压状态,且未发生任何破坏,荷载作用位置及作用面积是影响仰拱预制块应力的重要因素;(4)本研究成果可应用于矿山法隧道及地下工程领域,为隧道智能化建造提供技术支撑。

Research purposes:Compared with the traditional cast-in-place concrete structure,the prefabricated structure has the advantages of high standardization,convenient construction,small site occupation,high mechanization and environmental protection.When the prefabricated inverted arch is used in the mine method tunnel,the stress condition in the construction period should be considered in addition to the stress condition in the operation period.Therefore,the stress condition of the structure should be studied under the action of construction machines and tools,assembly machines,etc.Taking single track railway tunnel as the engineering background,the mechanical characteristics of precast invert block under construction load are studied through full-scale test.Research conclusions:(1)When the longitudinal tension of a single hole reaches 373 kN(37.3 t),the minimum circumferential seam can be closed.(2)The tightening effect is related to the tightening sequence and mode,and the proper tightening mode can improve the tightening effect.(3)During the whole process of construction load,the reinforcement and concrete are in compression state without any damage.The location and area of load action are important factors affecting the stress of inverted arch block.(4)This research result can be applied to the fields of mining tunnels and underground engineering,provide technical support for intelligent construction of tunnels.