隧道装配式预制仰拱结构选型研究

Research on the Selection of Prefabricated Inverted Arch Structures in Tunnels

对钻爆法隧道装配式预制仰拱结构选型设计进行研究。对比3类8种断面仰拱的力学性能,初步选择减重较多、力学性能较合理的3种断面并进行有限元分析。通过对整体模型和预制仰拱单块模型的对比研究,得出预制仰拱在施工机械荷载下的强度及稳定性。结合计算结果提出最优断面型式,采用该断面型式的仰拱预制块相较于原设计,重量减少8.78 t,减少百分比43.9%,按承载力及正常使用极限状态设计均能满足要求。对其经济性进行分析对比,UHPC混凝土材料费用与原设计基本持平,当预制仰拱采用15 cm厚的UHPC板时,应力集中明显减少,塑性区域也较为合理和安全,可以作为预制仰拱的推荐型式。

This article mainly studies the structural selection design of the prefabricated inverted arch for tunnels by drilling and blasting method.Compared with the mechanical properties of eight types of inverted arches in three categories,three types of sections with more weight reduction and reasonable mechanical properties are preliminarily selected and finite element analysis is performed.By comparing the overall model and the prefabricated inverted arch single block model,the strength and stability of the prefabricated inverted arch under construction machinery loads are obtained.Based on the calculation results,the optimal section type is proposed.Compared with the original design,the weight of the inverted arch prefabricated block using this section type is reduced by 8.78 tons,with a reduction percentage of 43.9%,and both the bearing capacity and normal use limit state designs can meet the requirements.Analysis and comparison of its economy show that the material cost of UHPC is basically the same as the original design.When using 15 cm UHPC panels for prefabricated inverted arches,stress concentration is significantly reduced,and the plastic area is also reasonable and safe,making it a recommended type of prefabricated inverted arches.