磷石膏基复合充填材料力学性能试验研究

摘要

针对黄麦岭露天转地下充填开采为背景,对该矿的磷石膏复合充填体进行室内单轴抗压强度正交试验,研究不同的料浆质量浓度、磷石膏、粉煤灰、水泥的含量及拌合水pH值等5个因素对充填材料力学性能的影响.对不同配比的复合充填体在分别养护7d、14 d和28 d后的单轴抗压强度进行测试,同时研究各组配比的坍塌度和泌水率,通过DPS和MATLAB优化工具箱对试验数据进行多元回归分析,最终得到了复合充填材料的优化配比,研究结果表明:当质量浓度为77％、拌合水pH值为12.9,磷石膏、粉煤灰、水泥在比值为5∶12∶3时充填体强度为4.87MPa,坍塌度为208.82 mm.对优化配比进行了试验验证,表明28 d的充填体强度为5.13 MPa,对应坍塌度为196mm.该成果为黄麦岭矿利用磷石膏和粉煤灰提供了理论依据.%Taking backfill tailings of Huangmailing phosphorus Mine as research background,the orthogonal test was carried out to research the uniaxial compressive strength (UCS) of composite backfills with phosphorus gypsum.Through the orthogonal test,the effect of five factors including different mass concentration,mass of phosphorus gypsum,coal ash,the percentage of cement and PH value of mixing water on the mechanical property of backfills are investigated.The UCS of composite backfills with different proportions at 7,14 and 28 d was tested.And the collapse degree and the bleeding rate of each composite backfill were also tested respectively.Then the optimal ratio of backfilling composition was obtained after the experimental data were analyzed by DPS method and MATLAB optimization toolbox with regression analysis.The results showed that under conditions of mass ratio 77％ and Ph value 12.09 of mixing water,the UCS and collapse degree of backfills are 4.78 MPa and 208.82 mm respectively when the ratio of phosphorus gypsum,coal ash and cement is 5 ∶ 12 ∶ 3.The optimization ratio tests verified that the UCS and collapse degree of backfills are 5.13 MPa and 196 mm respectively when the curing time is at 28 d.Therefore,the research results provide theoretical basis for the utilization of phosphor gypsum and coal ash from Huangmailing Mine.