超浅埋暗挖隧道优化CRD法施工技术

Optimized CRD Construction Techniques for a Super-Shallow Bored Tunnel

文章基于深圳市城市轨道交通9号线给排水管线改迁及恢复工程箱涵暗挖段施工实例,针对传统的CRD隧道施工方法存在的不足,提出了超浅埋暗挖隧道优化CRD法施工技术。该优化CRD法技术原理是:首先,通过对隧道围岩进行注浆加固,保证工作面处于稳定状况;其次,施作超前大管棚、超前小导管,与型钢拱架联合发挥棚架作用,避免拱部坍塌的危险,有效减小地表沉降;第三,在保证支护结构安全稳定的前提下,优化临时仰拱、中隔墙的临时钢架,将临时仰拱优化为临时型钢梁,取消临时仰拱、中隔墙的挂钢筋网及喷混凝土施工;第四,将隧道分成4个工作面,同时开挖,逐步成环,保证快速安全地进行土方开挖。文章重点对隧道土方开挖、型钢钢架安装的关键施工技术进行了详细论述。该技术应用于超浅埋暗挖隧道施工,既保证了隧道施工的安全,又降低了施工的成本,加快了施工进度,取得了显著效果。

To address the shortcomings of the traditional CRD method for tunnel construction, optimized CRD con-struction techniques were proposed for a super-shallow bored tunnel based on the construction of a box culvert for the water supply and drainage project of Shenzhen＇ s urban transit rail line 9. Grouting reinforcement was selected for the surrounding rock to guarantee a stable work face, and a large advance pipe roof and small conduit were con-structed to work with the steel frame to avoid crown collapse and effectively reduce surface settlement. The tempo-rary invert and steel frame of the center cross diaphragm were optimized, and the construction of the steel reinforce-ment and shotcrete for the temporary invert and center cross diaphragm were disregarded. The into four work faces to be excavated at the same time. Significant achievements were achieved applied to the super-shallow bored tunnel, including safe construction, reduced cost and rapid project was divided with this technique construction speed.The key techniques for earth excavation and profile steel frame installation are described here in detail.