大型地下水封洞库开挖爆破方式优选

Optimization and Selection of Blasting Method for the Excavation of Large-scale Underground Water-sealed Caverns

为合理选择大型地下水封洞库施工爆破方式,采用爆破试验的方法,结合爆破振动测试、爆前爆后声波检测、爆后宏观调查等手段,比较分析了深孔台阶爆破+预裂爆破和水平浅孔爆破+光面爆破2种爆破方案的优劣。分析可知:深孔台阶爆破+预裂爆破方案下爆破振动及围岩损伤均大于水平浅孔爆破+光面爆破,但仍在可控的范围内,二者均满足地下水封洞库开挖轮廓面成形的要求。故深孔台阶爆破+预裂爆破方案可用于大型地下水封洞库的开挖,但需要严格控制钻孔精度、单段起爆药量、药包直径以及装药结构;水平浅孔爆破+光面爆破方案适合在岩体性质较差或爆破振动控制相对较严格的开挖区域中采用。

The selection of a reasonable blasting method is one of the key issues in the construction of large underground water-sealed caverns. Through field blasting test,blasting vibration monitoring,sound wave detection before and after blasting,as well as macroscopic investigation after blasting,we compared and analyzed the advantages and disadvantages of two blasting methods: deep hole bench blasting plus pre-splitting blasting,and horizontal shallow hole blasting plus smooth blasting. Results indicate that the blasting vibration and surrounding rock damage of the former method are greater than those of the latter,but still in controllable range and both methods meet the requirements of underground water-sealed cavern excavation molding. It's concluded that the former method can be used for the excavation of large underground water-sealed caverns,but the drilling accuracy,single delay charge weight,charge diameter and charge structure should be strictly controlled. The latter method suits the excavation which requires strict control of blasting vibration or with poor rock mass.