公路隧道通风竖井及支护施工技术研究

Research on Construction Technology of Highway Tunnel Ventilation Shaft and Support

以杭州市紫之隧道工程土建第Ⅱ标段1#竖井与2#竖井为工程实例进行通风竖井及支护施工技术研究。对施工工艺中各关键步骤进行分析共得出以下几点结论:给出了钻孔爆破方法,炸药用量计算方法及孔洞分布位置设计原则;第一次爆破先在竖井中心从上向下凿岩机凿孔,采用桶形爆破法,凿孔深度2~2.5 m,炮眼排距0.9 m,每孔装药量平均1.28 kg,爆破形成直径2.5 m导洞至下层通道。井身开挖采取上而下爆破、循环进尺、每次深度按2 m开挖,逐次往里下挖方式。开挖全部完成后进行竖井初支与二次衬砌,二次衬砌每10 m设一壁座,壁座尺寸在普通衬砌结构的基础上加大150 cm;待加强段衬砌砼强度达到设计70%后,继续搭设脚手架,安装模板,自下而上依次衬砌施工。

In Hangzhou purple tunnel civil engineering II section 1# and 2# shaft as an example of shaft ventilation shaft and supporting construction technology research. The key step in the construction process were analyzed to draw the following conclusions： given the drilling and blasting method,calculation method and design principle of hole distribution amount of explosive blasting in shaft; the first first down from the center drill borehole,using a barrel blasting method,chisel hole depth 2 m ～ 2. 5 m,hole row spacing of 0. 9 meters. The average 1. 28 kg per hole charge,blasting the formation of 2. 5 meters in diameter and heading to the lower channel. Well take and excavation blasting,circulation footage,the depth of every 2 meters according to the excavation,successive to dig under way. All after the completion of excavation and shotcrete lining shaft two,two lining each 10 m set a seat,seat wall size increase150 cm based on ordinary lining structure; to strengthen the segment lining concrete strength to meet the design 70%,continue to scaffolding installation template,lining construction from bottom to top.