水库排沙洞进口岩坎爆破技术研究

Technical Research on Rock Bar Blasting in Inlet of Reservoir Desilting Tunnel

水库排沙洞进口一般在淤泥以下较深位置，其开挖难度较大，当进口不能采用常规开挖方法时需采用岩坎或岩塞爆破；岩坎爆破是河北省庙宫水库除险加固工程排沙洞开挖的关键，岩坎上部厚度为5m，下部厚度10m，为了保护边坡、围岩的稳定和周围建筑物的安全，根据岩坎的尺寸和围岩状况，采用水平与竖向相结合、深孔与浅孔相结合、大孔径与小孔径相结合的钻孔方式，采取合理的爆破参数，严格爆破控制单响药量，成功地完成了岩坎爆破，达到预期的效果。

The inlet of reservoir desilting tunnel is generally located in deep mud that makes it difficult to be excavated. When the inlet can not be excavated in conventional ways, rock bar or rock plug blasting will be used. Rock bar blasting is the key to desilting tunnel excavating of rehabili tation of Hebei Miaogong Reservoir. The upper part of rock bar is 5 meters and the lower part is 10 meters. To protect the stability of slope and wall rock as well as the safety of surrounding buildings and in the mean time according to the size of rock bank and state of wall rock, the drilling way of the combination of horizontal and vertical, deep-hole and shallow-hole as well as large-diameter and small diameter is used. Furthermore, the reasonable blasting parameter is applied and quantity of explosive of once triggered is strictly controlled. Therefore, the rock bar blasting has been successfully carried out and the expected effect has also been paid off.