露天矿高深溜井降段技术

露天矿采区内的溜井,随开采台阶面的下降需要降段。甘肃某露天矿山采区内的3#、4#溜井,其溜井深度均在400m以上,且区域地质结构复杂,井壁采用800mm厚钢钎混凝土支护,降段技术要求高、施工难度大,不能采用以往的以溜井口为自由面进行爆破降段,据此提出了一种先通过掘沟爆破为溜井降段提供自由面,再采用预裂爆破技术保护溜井支护体的完整性,最后通过深孔爆破和浅孔爆破相结合,完成溜井全降段的综合性降段技术。实践应用表明,该综合技术不仅满足了安全生产要求,而且取得了良好的爆破效果和经济效益。

DEMOLITION BLASTING DESIGN OF THE DEEP COVER NON HOMOGENEOUS AND COMPLEX STRUCTURE COFFERDAM

In Guandi Hydropower Station,tail water outlet cofferdam has characteristics of deep cover, non homogeneous,unloading bedrock and complex structure,the distance between cofferdam and exit gate or hoist are≤30m,lock chamber and open channel base plate between cofferdams are 1:4 adverse slope, channel structure concrete connects with cofferdam,the distance of mixing floor across the river is≤90m, the blasting demolition of it is large scale and high demand.The scheme selection,parameters and blasting network design of the cofferdam demolition blasting,blasting safety protection and construction technical measures were also introduced,which could be a reference for the similar projects.