新型隧道结构纵向连接筋对支护性能影响研究

隧道工程中,纵向连接筋多为焊接或者插入式连接,但纵向连接筋对隧道支护性能影响尚不明确,没有相关试验分析。基于此问题,按照初支二衬联拱隧道新型支护体系,设计采用不同纵向连接筋形式初期支护构件,采用MTS大型拟动力加载系统进行室内加载试验,对采用纵向连接筋构件的力学特性进行研究,得到如下结论:(1)纵向连接筋在初期支护中稳定型钢、参与结构受力,加强隧道支护承载能力及抗变形能力,提升隧道整体性、稳定性;(2)纵向连接筋插入式连接在提升构件承载力及抗变形能力要优于焊接连接,该影响主要体现在加载后期;(3)该试验对比了几种不同纵向连接筋构件受力及变形情况,根据试验结果可确定纵向连接筋最优设置形式,为实际工程提供参考。

Research on the Influence of New Tunnel Structure Longitudinal Connecting Bar on Supporting Performance

In tunnel engineering, longitudinal connecting bar is mostly welded or plug-in connected, and it is widely used in tunnel construction. However, the influence of longitudinal connecting bar on tunnel support performance is not clear and there is no relevant experimental analysis. Based on the above-mentioned problems and according to the new supporting system of primary support and secondary lining arch tunnel, this paper designs the primary supporting members with different forms of longitudinal connecting bar, adopts MTS large-scale pseudo-dynamic loading system to carry out indoor loading tests, and studies the mechanical characteristics of the members with longitudinal connecting bar. The following conclusions are obtained:(1) The longitudinal connecting bar stabilizes the section steel, participates in the structural stress, strengthens the bearing capacity and deformation resistance of the tunnel support, and improves the integrity and stability of the tunnel.(2) The longitudinal connecting bar of plug-in connection is better than welded connection in enhancing the bearing capacity and anti-deformation capacity of the member, and the influence is mainly reflected in the later stage of loading.(3) The test compares the stress and deformation of several different longitudinal connecting bar members. According to the test results, the optimal setting form of the longitudinal connecting bar can be determined, which provides certain reference for practical engineering.