混杂纤维掺量对尾砂充填体力学性能影响研究

为了探究混杂纤维掺量对尾砂胶结充填体力学性能的增强效果，选取三种纤维材料进行坍落度、单轴压缩和SHPB冲击试验。结果表明：纤维材料对充填体流动性影响较大，纤维掺量越高时流动性越弱，其中聚丙烯纤维对流动性影响最显著；混杂纤维对充填体的动、静力学性能提高幅度均受混杂纤维掺量影响，在一定范围内随纤维掺量增高呈现先变大后减小的趋势，0.4%质量分数的聚丙烯纤维对充填体早期抗压强度增幅最为显著，28d标准养护龄期时钢纤维对充填体动、静力学性能的提高均大于另外两种纤维；总纤维掺量在1.4%~1.5%的混杂纤维对充填体动态抗压强度提高最大，提高幅度大于更高或更低纤维掺量的方案；在相同的平均应变率下，随着混杂纤维掺量增加，充填体的反射能和吸收能先减小后增大，透射能先增大后减小。试验结果表明适量的混杂纤维可以有效提高充填体的力学性能，有利于充填开采的安全性，同时对矿山充填体材料设计具有一定指导作用。

Study on the influence of hybrid fiber content on the comprehensive mechanical properties of tailings filling body

In order to explore the enhancement effect of hybrid fiber content on the mechanical properties of cemented tailings backfill, three kinds of fiber materials were selected for slump, uniaxial compression and SHPB impact tests. The test results show that the fiber material has a great influence on the fluidity of the filling body. The higher the fiber content is, the weaker the fluidity is, and the polypropylene fiber has the most significant influence on the fluidity. The improvement of dynamic and static mechanical properties of filling body by hybrid fiber is affected by the content of hybrid fiber. In a certain range, with the increase of fiber content, it shows a trend of increasing first and then decreasing. The 0.4 % mass fraction of polypropylene fiber has the most significant increase in the early compressive strength of filling body. At the standard curing age of 28 days, the improvement of dynamic and static mechanical properties of filling body by steel fiber is greater than that of the other two fibers. The hybrid fiber with a total fiber content of 1.4 % ~ 1.5 % has the largest increase in the dynamic compressive strength of the filling body, and the increase is greater than that of higher or lower fiber content. At the same average strain rate, with the increase of hybrid fiber content, the reflection energy and absorption energy of the filling body decrease first and then increase, and the transmission energy increases first and then decreases. The test results show that the appropriate amount of hybrid fiber can effectively improve the mechanical properties of the filling body, which is conducive to the safety of filling mining, and has a certain guiding role in the design of mine filling body materials.