碎石及纤维对细粒级尾砂充填体强度影响研究

Research on the Influence of Crushed Stone and Fiber on the Strength of Filling Body with Fine-grained Tailings

针对如何提高细粒级尾砂充填体强度的问题,探索添加不同破碎细度碎石、不同长度聚丙烯纤维对细粒级尾砂充填体强度的影响。结果表明:碎石添加有利于充填体强度的提高,碎石的级配、添加比例是关键因素,其中碎石尾砂质量比为1∶10时充填体强度最优,3 d、7 d、14 d、28 d单轴抗压强度可分别提高47.5%、94.8%、90.6%、85.3%,对应充填料浆屈服应力降低47.86%,黏度降低25%;纤维的添加有利于提高充填体的单轴抗压强度、抗弯强度及剪切强度,添加量宜在0.2%~0.6%之间,且18 mm聚丙烯纤维对充填体强度及韧性的提高效果优于6 mm纤维,7 d充填体单轴抗压强度、抗弯强度、剪切强度能分别提高15.36%、24.91%、29.49%;添加纤维有利于提高充填体峰后残余强度,使充填体在承压时能保证更好的整体稳定性。研究结果为黄金矿山使用细粒级尾砂充填时优化充填体强度提供参考依据。

Aiming at the problem that how to improve the strength of filling body with fine-grained tailings,the influences of crushed stones with different crushing finenesses and polypropylene fibers with different lengths adding in filling body were studied on the strength.The results show that the addition of crushed stone is beneficial to the improvement of the strength of the filling body.The particle size composition and addition ratio of the crushed stone are the key factors.When the mass ratio of crushed stone to tailings is 1∶10,the strength of the filling body is the best,the uniaxial compressive strength in 3 d,7 d,14 d and 28 d is increased by 47.5%,94.8%,90.6%and 85.3%,respectively,the yield stress of filling slurry is reduced by 47.86%,and the plastic viscosity is reduced by 25%correspondingly.The addition of fiber is beneficial to improve the uniaxial compressive strength,bending strength and shear strength,and the addition amount should be between 0.2%and 0.6%.Polypropylene fiber with length of 18 mm has a better improvement effect on the strength and integrity than that of 6 mm.The compressive strength,bending strength and shear strength of the filling body in 7 d can be increased by 15.36%,24.91%,and 29.49%respectively.The addition of fibers is beneficial to increase the residual strength of the filling body after the peak,which enables the filling body to ensure better overall stability when the filling body is under pressure.The research results can provide a reference for the optimization of the backfill strength when fine-grained tailings is used in gold mines filling.