裂隙发育岩体水电工程地下洞室预裂爆破试验研究  

Experimental Study on Pre-splitting Blast of Underground Caverns in Fractured Rock Mass

作　　者：陈星艮 关富僳 付兆凯 纳小平 郝利军[3] 李洪涛[1] CHEN Xing-gen;GUAN Fu-su;FU Zhao-kai;NA Xiao-ping;HAO Li-jun;LI Hong-tao(College of Water Resource&Hydropower,Sichuan University,Chengdu 610065,China;Sichuan Water Development Investigation Design and Research Co.,Ltd.,Chengdu 610065,China;Sinohydro Bureau 5 Co.,Ltd.,Chengdu 610066,China)

机构地区：[1]四川大学水利水电学院,成都610065 [2]四川水发勘测设计研究有限公司,成都610065 [3]中国水利水电第五工程局有限公司,成都610066

出　　处：《爆破》2024年第2期67-74,共8页Blasting

基　　金：国家重点研发计划项目(2023YFC3008305);四川省国际科技合作计划项目(2022YFH0078);国家自然科学基金项目(51809188)。

摘　　要：硬梁包水电站地下厂房地质构造复杂,围岩裂隙发育,岩性杂乱,岩体具有“硬、碎、杂”特点,厂房开挖成型难度较大、预裂爆破效果差,为解决此问题,结合地下厂房第Ⅲ层中部拉槽施工预裂,开展了系统的爆破试验。初期试验中,预裂爆破线装药密度低于规范计算值近100 g/m的情况下,两侧边墙岩体在爆破后十分破碎,无法明显看到预裂孔的痕迹。开展的岩体声波测试和岩体完整性分析表明:厂房岩体全孔平均纵波速度为4.03 km/s,整体完整性差;岩体沿预裂孔轴向0~1.5 m、1.5~3.9 m、3.9~7.4 m深度的分段波速平均值分别为2.59 km/s、3.58 km/s、4.70 km/s,表现出在深度方向上的分段完整性差异。根据上述特点,在厂房开挖施工过程中,预裂爆破的平均单孔线装药密度取为0.123~0.284 kg/m,并针对不同深度选取不同的线装药密度,各分段采用小药卷均匀间隔装药,试验和应用效果良好,保证了壁面基本成型,半孔率显著提高。The geological structure of the Ying Liang-bao hydroelectric underground power-house is complex due to the development of surrounding rock fissures,messy lithology,and a rock body with"hard,broken,miscellaneous"characteristics.Excavation and molding pose difficulties while pre-splitting blasting has poor effects.To address this issue,we conducted a systematic blasting test combined with pre-splitting for central groove construction on layerⅢof the power-house.In initial tests,both sides of the wall exhibited significant breakage after blasting and traces of pre-splitting holes were not clearly visible when linear charge density was nearly 100 g/m lower than standardized calculation values.Acoustic testing data revealed that average longitudinal wave velocity in the rock mass body was 4.03 km/s indicating overall poor integrity.Additionally,segmental wave velocities along axial depths from 0~1.5 m,1.5~3.9 m and 3.9~7.4 m were found to be 2.59 km/s,3.58 km/s and 4.70 km/s respectively suggesting segmented integrity differences in depth direction.Based on these findings an average single-hole linear charge density for pre-splitting blasts during excavation was determined to be between 0.123~0.284 kg/m with different densities selected according to varying depths while small charge rolls were evenly spaced for each section.The results obtained through testing and application have been positive ensuring basic formation of wall surfaces while significantly increasing half-porosity levels.

关 键 词：地下洞室 裂隙发育岩体 预裂爆破 参数优化 装药结构 

分 类 号：TD235[矿业工程—矿井建设]