茅坪山隧道2#横洞进入正洞施工技术

Construction Techniques for the 2# Level Drift Going into the Main Hole of the Maopingshan Tunnel

以沪昆客专茅坪山隧道为研究对象,介绍了橫洞进入正洞施工技术方案的实施,即2#横洞施工至正洞左中线后,用弧形圆顺的方式进入正洞大里程方向,然后按照横洞净空尺寸上坡开挖至正洞拱顶高程,并继续沿大里程方向施工10m,扩挖支护达到正洞标准尺寸、形成作业空间后,转向相反方向施工。介绍横洞进入正洞的挑顶施工技术,交叉口位置支护加固处理、仰拱施工技术的综合应用。上述技术使横洞进入正洞施工进展顺利,无事故发生,确保了施工进度,缩短了施工工期,节约了施工成本,提高了施工经济效益,可为类似工程提供有益借鉴。

With the Maopingshan Tunnel of the Shanghai-Kunming Passengers-oriented Railway as a practical example,the implementation of the technical scheme of construction for a level drift going into the main hole is introduced in the paper.According to the construction scheme,when the 2#level drift is excavated till the left central line of the main hole,it will go smoothly into the main hole in the big range direction in the shape of an arc,then it will be excavated till the height range of the arch top of the main hole according to the clearance requirements of the level drift,after which it will be dug ten metres in the big range direction of the main hole.When the level drift is expanded to the standard size of the main hole,the support is completed and the working space is formed,the excavation construction will be performed in the opposite direction.The roof ripping construction techniques for the level drift going into the main hole,the intersection position supporting reinforcement,the comprehensive application of the inverted arch construction techniques are all introduced in the paper.The above-mentioned techniques ensure the smooth and safe construction of a level drift going into the main hole,with no accident occurring,the construction progress schedules implemented,the construction duration shortened,construction costs saved and economic efficiency and benefit achieved.The project may serve as a useful reference for other similar projects.