魏家峁煤矿区深孔台阶剥离爆破施工岩体可爆性分析

Analysis on Rock Mass Explosibility During Deep-hole Bench Stripping by Blasting in Weijiamao Coal Mine Area

了解和掌握岩体可爆性分级是确定合理爆破参数和提高工程效率的重要依据。结合魏家峁矿区台阶爆破开挖实际,在现场调查、取样基础上,根据矿区工程地质资料得到岩样的普氏系数和抗拉强度。采用蜡封法密度试验和岩石声波试验对已揭露台阶面岩样的岩石密度、声波波速进行了测试分析。依据获取的四个指标,基于加权聚类分析原理对矿区岩体可爆性进行了研究。研究表明:魏家峁矿区剥离层岩石有粗砂岩、中砂岩、细砂岩、砂砾岩和泥砂岩等。试验得到的五种岩石密度中,泥砂岩密度最大,为2.75 g/cm^(3);粗砂岩密度最小,为2.01 g/cm^(3),砂砾岩、细砂岩、中砂岩密度位于泥砂岩和粗砂岩之间。在声波试验得到的平盘所对应岩样的声波波速中1064平盘的岩石纵波波速最大,为2.615 km/s,1096平盘的岩石纵波波速最小,为2.029 km/s。根据所取岩样对应的平盘分布状况,魏家峁矿区剥离岩体的可爆性从1112平盘至1064平盘自上而下逐渐变差,其中1112平盘主要是砂砾岩,可爆性为中等难爆;1096平盘以粗砂岩为主,可爆性为易爆;1080平盘是中砂岩,可爆性为中等难爆;1064平盘主要岩性为细砂岩,可爆性为难爆。

Understanding the classification of rock mass blastability is an important basis for determining reasonable blasting parameters and improving engineering efficiency.Combined with the practice of bench blasting in Weijiamao mining area,the protodyakonov coefficient and the tensile strength of rock samples are obtained according to the engineering geological data of the mining area,on the basis of site investigation and sampling.The density and acoustic wave velocity of the rock samples on the exposed step surface are measured and analyzed by wax sealing density tests and acoustic wave tests.According to the four indexes obtained,the rock mass blastability in the mining area is studied based on the principle of weighted cluster analysis.The research shows that there are coarse sandstone,medium sandstone,fine sandstone,sandy conglomerate and argillaceous sandstone in the Wejiamao mining area.The density of the marl sandstone is the highest,which is 2.75 g/cm^(3).The density of the coarse sandstone is the lowest,2.01 g/cm^(3),while the density of the sandy conglomerate,fine sandstone and medium sandstone lies between the marl sandstone and the coarse sandstone.In the acoustic wave test,the longitudinal wave velocity of the rock in the 1064 platform is the highest,which is 2.615 km/s,while that in the 1096 platform is the lowest,which is 2.029 km/s.According to the distribution of the rock samples at the corresponding platform,the blastability of the rock mass in Weijiamao mining area gradually decreases from 1112 platform to 1064 platform.Among them,the 1112 platform is mainly sandy conglomerate with a medium blastability.The 1096 platform is mainly coarse sandstone with an easy blastability.The 1080 platform is medium sandstone with a medium blastability.The 1064 platform is mainly composed of fine sandstone with a difficult blastability.