复杂环境下既有隧道扩挖爆破技术

Expansion blasting technique of existing tunnel in complex environment

针对复杂环境下既有浅埋隧道扩挖工程具有围岩风化严重、开挖方式单一、保留边帮易受损和爆破振动难控制的特点,以某隧道K116+140~K116+312段扩挖工程为实例,综合分析、研究了该隧道扩挖工程的难点,依据以往隧道掘进施工经验,提出了隧道上部超前开挖法,台阶钻爆法、光面爆破技术和有效的爆破安全措施。同时通过精细化的装药结构设计和起爆网路的连接,控制了爆破振动对既有隧道的危害,确保了隧道扩挖壁面的平整,达到了预期的扩挖要求,可为类似隧道扩挖工程提供经验借鉴。

In the complex environment,the shallow tunnel excavation project has the characteristics of severe weathering of surrounding rock,single excavation mode,easy to damage the retaining edge and difficult to control blasting vibration.Taking the expansion project of K116+140~K116+312 section of a tunnel as an example,through comprehensive analysis and research on the difficult points of the tunnel expansion project,based on the previous tunneling construction experience,the upper advanced excavation method,step drilling explosion method,smooth blasting technology and effective blasting safety measures are adopted.At the same time,through the refinement of the charge structure design and the connection of the detonation network,controlling the damage of blasting vibration to existing tunnels,ensuring the smoothing of the wall surface of the tunnel expansion,and meeting the expected expansion requirements.It can provide experience for similar tunnel expansion projects.