早强剂对固结粉胶凝材料混合骨料充填体强度的影响

为实现废石和固结粉胶凝材料在金川矿区充填采矿中的应用，首先开展了不同配比废石—棒磨砂混合骨料粒径级配分析，获得废石与棒磨砂配比为4∶6混合骨料的堆积密实度为0.635和泰波幂指数n为 0.591；然后，针对废石含量为10%~50%的混合骨料，分别开展了添加和不添加早强剂的固结粉胶结充填体强度试验。结果表明：充填体强度随着废石含量增加呈现先提高后降低趋势。当废石含量为40%，料浆浓度为 79%~81%时，不添加早强剂的固结粉胶结充填体3、7、28 d平均强度分别达到1.23、3.79、5.98 MPa，其早期强度低于矿山设计强度；添加早强剂时，胶结充填体3、7、28 d平均强度分别达到1.55、3.34、6.46 MPa， 满足金川矿区下向分层进路胶结充填采矿作业对胶结充填体强度的要求。由此确定，胶砂比1∶5、废石∶棒磨砂4∶6、浓度79%~81%、添加1%早强剂的固结粉胶凝材料混合骨料可在金川矿区推广应用。

Effects of Early Strength Accelerators on the Strength of Filling Body Comprised of Consolidated Powder and Mixed Aggregate

For the utilization of waste rock and consolidated powder in Jinchuan mining area，firstly，the particle size grading analysis of mixed aggregate was carried out with different ratio of waste rock to rod mill sand.The results show that the packing density and Talbol power index n of the mixed aggregate with ratio of 4∶6 were 0.635 and 0.591 respectively.Then，as the ratio of waste rock in mixed aggregate increasing from 10% to 50%，unconfined compressive strength tests were taken for the filling body with and without early strength accelerators respectively.The study results show that the strength of fill body increases firstly and then decreases as the increasing of waste rock content.When the ratio of waste rock is 40% and the slurry mass concentration is 79%~81%，the average strength of fill body without early strength accelerators in three curing periods （3 d，7 d and 28 d） was 1.23 MPa，3.79 MPa and 5.98 MPa respectively，and its early strength is lower than the mine designed strength.By adding early strength accelerators，the average strength of filling body in three curing periods reached 1.55 MPa，3.34 MPa and 6.46 MPa respectively，meeting the needs of cemented backfill strength by the downward slicing drift mining operation in Jinchuan mining area.Therefore，with cement- aggregate ratio of 1∶5，waste rock-rod mill sand ratio of 4∶6，slurry mass concentration of 79%~81%，the mixture comprised with consolidation powder，mixed aggregate and 1% early strength accelerators could be widely applied in Jinchuan mining area.