【摘要】 为研究深井矿山全尾砂胶结充填体的早期强度特性,以某铁矿全尾砂为试验材料,在分析该矿全尾砂材料的粒径级配组成、化学成分等基本物理化学特性基础上,制备了灰砂比1∶4、1∶6、1∶8和料浆浓度为59%、62%和65%的充填体试样,测定龄期为3d和7d时单轴抗压强度,并借助扫描电镜(SEM)对充填体微观结构进行观察与分析。结果表明:超细全尾砂胶结充填体早期强度较低,充填体强度与灰砂比、料浆浓度和龄期存在正指数关系,且随着龄期的增加,充填体强度增长显著。SEM显示,当充填体龄期为3d时钙钒石和C-S-H凝胶体生成量较少,胶凝物对尾砂的包裹效果较差,充填体内部存在较大空隙,结构松散,表现为强度较低;充填体龄期为7d时钙钒石被凝胶包裹,充填体内部空隙逐渐缩小,结构密实,表现为强度增长。超细全尾砂胶结充填体早期强度对龄期敏感程度最高,灰砂比次之,料浆浓度较低。更多还原

【Abstract】 In order to study the early strength characteristics of cemented full tailings filling in deep mines,the unclassified tailings from an iron mine was used as experimental raw material.The backfill samples with the cemented-sand ratio of 1∶4、1∶6、1∶8 and the slurry concentration of 59%,62%,and 65% were prepared after analyzing the basic physicochemical properties such as the particle size distribution and chemical composition of the tailings of the mine.The uniaxial compressive strength at 3 dand 7 dwere measured,and the microstructure of the filling body was observed and analyzed by using scanning electron microscope(SEM).The results show that the early strength of the ultrafine cemented full tailings filling body is low,and there is a positive exponential relationship between the strength of the backfill and the ratio of lime to sand,slurry concentration and age,and the strength of filling body increases significantly with the increase of age.SEM showed that the amount of ettringite and C-S-H gel generated was less when filling age was 3 d,and the effect of gelling on tailings was poor,and there were many big gaps in the filling body.The structure was loose and showed the strength was lower.When the filling body age was 7 d,the ettringite was packaged by gel coating and the gaps of filling body were gradually reduced,and the structure got dense,showing strength growth.The early strength of the ultrafine full tailings cemented backfill is the most sensitive to age,followed by cement-tailing ratio,and the slurry concentration is lower.更多还原