高速铁路隧道洞口接长明洞方案研究与实践

Study and Practice on the Scheme of Extending Open-cut Tunnel Section from the Portal of High-speed Railway Tunnel

本文针对郑西高速铁路联调联试阶段黄土隧道洞口高边坡影响行车安全要求增设明洞的问题,从设计方案与工程实施的方便可行性角度出发,结合外方咨询意见,研究分析了采用单跨或多跨框架棚洞、拱形明洞两种结构型式,并通过数值计算分析确定了两种结构型式的内力及配筋。研究结果表明:采用桩基托梁拱形明洞方案更为合理可行,并通过采用H型钢内缘设纤维混凝土板作为内模的结构型式,解决了接触网导线条件下内模安装难题。分析认为,针对高速铁路运营条件下帽檐斜切式洞门接长明洞,采用本文介绍的方案具有较好的可实施性。

Aiming at the requirement of adding open-cut tunnel sections due to the high slope at the portal of loess tunnel that affects the operation safety in the integrated commissioning&test stage of Zhengzhou-Xi an High-speed Railway,and assisted by the external consultants,this paper studies and analyzes the scheme of adopting single-span or multi-span frame shed tunnel and arch open tunnel from the perspective of design proposal and the engineering feasibility,and determines the internal force and reinforcement of the two structures through numerical calculation and analysis.The results show that it is more reasonable and feasible to adopt the arch-shaped open-cut tunnel of pile foundation joist,and by adopting the structure type of inner edge of H-shaped steel with fiber concrete slab as internal mold,the problem of internal mold installation under the condition of catenary wire is solved.According to the analysis,the scheme introduced in this paper is feasible for the extension of the open-cut tunnel section with the brim inclined cutting type portal under the operation condition of a high-speed railway.