掺早强剂充填体在不同加载速率下裂隙破裂特性

与传统采矿法相比充填采矿法具有环保、安全等特点而在矿山生产中广泛使用,但充填过程中充填体会受到灰砂比、级配、料浆浓度等内在因素的影响,还受早强剂、加载速率等外在因素的影响。通过不同加载速率对掺早强剂与未掺早强剂充填体进行单轴压缩试验及声发射试验,对其力学性能和声发射特性进行研究。结果表明,充填体强度在不同加载速率下会呈现先增后减的趋势,且早强剂掺量不同时充填体的强度增幅也是不同的。而基于声发射特征参数RA和AF发现,随着加载速率的增加,剪切裂隙占比减少,在达到临界加载速率后随着速率的增加剪切裂隙增加。未掺早强剂充填体与掺早强剂充填体相比,在同等速率下加载所产生的剪切裂隙占比较多。

Fissure fracture characteristics of filling body with early strength agent under different loading rates

Compared with the traditional mining method, the filling mining method has the characteristics of environmental protection and safety, and is widely used in mine production. However, the filling experience in the filling process is affected by internal factors such as cement-sand ratio, gradation, slurry concentration, and external factors such as early strength agent and loading rate. Uniaxial compression test and acoustic emission test were carried out on backfill with and without early strength agent by different loading rates, and the mechanical properties and acoustic emission characteristics were studied. The results show that the strength of the filling body will increase first and then decrease under different loading rates, and the strength increase of the filling body is different when the dosage of the early strength agent is different. Based on the acoustic emission characteristic parameters RA and AF, it is found that the proportion of shear cracks decreases with the increase of loading rate, and the shear cracks increase with the increase of loading rate after reaching the critical loading rate. Compared with the filling body with early strength agent, the filling body without early strength agent has more shear cracks generated by loading at the same rate.