复杂地质条件隧道光面爆破及超挖控制技术研究

Research on Smooth Blasting and Overbreak Control Technology for Tunnels with Complex Geological Conditions

依托华东最长的杭绍台高铁东茗隧道工程,提出复杂地质条件下的隧道光面爆破和超挖控制技术。隧道原方案爆破后,围岩壁面粗糙、不规则,受力性能较差,半眼痕率较低,周边超挖较大。通过分析原方案爆破效果差及隧道超挖大的原因,提出减小周边眼间距,减少周边眼药量和装药系数,优化周边眼装药结构,提高钻孔精度,减少外插角等技术优化措施。优化后爆破方案的壁面光滑、规则,半孔保留率及炮孔利用率大幅提升,超挖现象得到明显改善,可为后续施工及类似工程提供科学指导,极大提高施工效率,综合经济效益显著。

Relying on the longest Hang Shaotai high-speed railway Dongming tunnel project in East China,the tunnel light surface blasting and overbreak control technology under complex geological conditions is proposed.After the blasting of the original tunnel scheme,the wall surface of the surrounding rock was rough and irregular,with poor force performance,low half-eye trace rate and large overbreak around,the maximum overbreak reaching 54.8cm and the average overbreak above 20cm.By analyzing the reasons for the poor blasting effect of the original plan and the large over-excavation of the tunnel,technical optimization measures such as reducing the perimeter eye spacing to 40cm,reducing the single-hole charge and charge factor of the perimeter eye,optimizing the perimeter eye to an interval three-stage charge structure,improving the drilling accuracy and reducing the interpolation angle to 3°~5°were proposed.The optimized blasting solution has a smooth and regular wall surface,a half-hole retention rate of more than 85%,a utilization rate of 93%and a maximum over-excavation of 0.221-0.276m and an average over-excavation of 0.107-0.172m.The over-excavation phenomenon has been significantly improved,which can provide scientific guidance for subsequent construction and similar projects,greatly improve construction efficiency and achieve significant comprehensive economic benefits.