不同骨料类型对充填体强度性能的影响及配比优化

Influence of Different Aggregate Types on Strength Performance of Backfill and Its Proportioning Optimization

为研究骨料类型对胶结充填体强度的影响规律,在室内开展了以全尾砂、尾砂—河沙及尾砂—废石为骨料的胶结充填体力学性能试验,分析了不同骨料类型下的充填体强度演化特征,并结合矿山对充填体强度指标的设计要求推荐了相应的骨料类型和配比参数。研究结果表明:采用全尾砂作为充填骨料时,砂灰比的增大会降低充填体强度,而料浆浓度的增大能够提高充填体的抗压强度,并且浓度的增加更有利于改善充填体的早期抗压强度;采用尾砂+河沙作为充填骨料时,三因素对充填体抗压强度的影响程度为砂灰比料浆浓度河沙含量,并且砂灰比的增大同样会降低充填体强度,浓度及河沙含量的增大有利于提高其强度;采用尾砂+废石作为充填骨料时,三因素对充填体3、7、28 d抗压强度的影响程度为砂灰比料浆浓度废石含量,砂灰比的增大会降低尾砂废石胶结充填体强度,浓度的增大有利于提高充填体强度。综合充填体强度及坍落度的测试结果,建议采用尾砂+废石作为矿山的充填骨料,配比参数可设计为灰砂比1∶6、料浆浓度76%、废石含量10%~15%。

In order to study the influence of aggregate type on the strength of cemented backfill,experiments on the physical properties of cemented backfill were carried out in laboratory with total tailings,tailings-river sand and tailings-waste rock as aggregate.The strength evolution characteristics of backfill under different aggregate types are analyzed,and the corresponding aggregate types and proportion parameters are recommended according to the design requirements of backfill strength index of mines.The results show that when the unclassified tailings is used as filling aggregate,the increase of sand-cement ratio will reduce the strength of the backfill,and the increase of slurry concentration can improve the compressive strength of the backfill,and the increase of concentration is more conducive to improving the early compressive strength of the backfill.When tailings and river sand are used as filling aggregate,the influence degree of the three factors on the compressive strength of the backfill is sand-cement ratio>slurry concentration>river sand content,and the increase of sand-cement ratio will also reduce the strength of the backfill,while the increase of concentration and river sand content is conducive to improving its strength.When tailings and waste rock are used as filling aggregate,the influence degree of the three factors on the compressive strength of the backfill at 3 d,7 d and 28 d is in the order of sand-cement ratio>slurry concentration>waste rock content.The increase of sand-cement ratio will reduce the strength of the backfill,and the increase of concentration is conducive to improving the strength of the backfill.Based on the test results of the strength and slump of the backfill,it is suggested to adopt tailing+waste rock as the filling aggregate of the mine.The proportion parameters can be designed as follows:the cement-sand ratio is 1∶6,the slurry concentration is 76%,and the waste rock content is 10%~15%.