预裂爆破在精河下天吉水库边坡开挖中的应用

精河县下天吉水库导流、泄洪、排砂洞工程进口明渠右岸边坡开挖。施工钻具为4台KQJ100B型潜孔钻机，马道二层，每层高20m，按马道层数，一次造孔至马道高程，分层、分段往进口明渠内抛掷的施工方法。炸药为20岩石硝氨炸药，分段、导爆索、电雷管引爆。预裂后成果半孔率54％～78％，预裂面平整度不大于20cm，坡比与设计相符，预留马道平台保护层厚度平均60cm，边坡平整度符合规范要求。

Application of Pre-splitting Blasting for Slope Excavation in Xiatianji Reservoir of Jinghe

The right bank slope of entrance open ditch for a diversion,flood-discharge and draining sand tunnel project in Xiatianji reservoir of Jinghe county is excavated.The methods of construction are: four KQT100 B down-the-hole drills are used for drilling instruments;the packway consists two layers;the height of each layer is 20 m;once-through borehole making reaches packway's altitude;throwing in the direction of entrance open ditch,by layers and sectionally;No.2 rock ammon-dynamite explosive is used with sectional detonating cord and electric detonator initiation.The achievements after pre-splitting are: half-borehole ratio ranges from 54 % to 78 %;flatness of pre-splitting face is not greater than 20 cm;the slope agrees with the value of design;the protective layer thickness of preplaced packway platform averages out 60 cm;the flatness of slope is up to the standard demand.