光面爆破设计是隧道工程建设确保质量安全的核心技术要素.青云山特长隧道是向莆铁路重点控制性工程,采用钻爆法施工;隧道围岩以Ⅱ～Ⅲ级为主,采用全断面法开挖;进出口与浅埋段等为Ⅳ、Ⅴ级围岩,采用台阶法施工;围岩较差段采用弧形开挖预留核心土法施工.不同级别围岩采用了针对性的爆破设计,取得了满意的爆破效果.实践证明,适当加密周边眼、合理确定光面爆破层厚度、采用小直径药卷不耦合装药结构、保证爆破眼同时起爆是光面爆破成功应用的关键.%Smooth blasting is a key technical element in ensuring the quality and safety of tunnel construction. The Qingyunshan Extra-long Tunnel on the Xiangtang-Putian Railway, which is one of its key projects, was built using the drilling-and-blasting method. For the surrounding rock of classes Ⅱ-Ⅲ, a full-face excavation was carried out. The bench method was used for the entrance, exit and the shallow-buried section with surrounding rock of classes IV and V. For poor quality rock masses, arc excavation with a reserved core was implemented. Applying different blasting schemes to different types of surrounding rock achieved very satisfactory results. This practice indicates that appropriate density of rim holes, reasonable thickness of blasting, small-diameter cartridge with a decoupled charging structure and simultaneous detonating are the key factors to guarantee successful smooth blasting.
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