考虑间歇充填和浓度效应的充填体长期强度试验研究

为探究不同充填间隔时间(FTS)和料浆浓度对胶结充填体长期强度影响机制，配制70%、72%、75%三个浓度、充填间隔时间为12、24、36、48 h的两分层胶结充填体试件，开展单轴抗压强度(UCS)试验并探究其力学特性及其破坏形式。试验结果表明，（1）胶结充填体峰值抗压强度随充填间隔时间增大而呈递减趋势，充填间隔时间一定时胶结充填体抗压强度随料浆浓度增大而增大，且峰值抗压强度与充填间隔时间呈多项式函数规律；（2）胶结充填体试件加载过程中表现为压密阶段、线弹性阶段、裂纹扩展阶段和破坏发展4个阶段，随充填间隔时间延长，胶结充填体的破坏形式可能表现为张拉破坏–拉剪破坏过渡–拉剪混合破坏的损伤模式。研究结论能够为后期充填体强度设计和稳定性控制提供有益参考。

Experimental study of long-term mechanical strength of cemented tailings backfill considering effect of filling interval time and solid content

In order to investigate the influence mechanism of the long-term strength of cemented tailings backfill(CTB) with different filling interval times(FITs) and solid contents(SDs). The uniaxial compression strength(UCS) test was carried out by using two layered CTB specimens with three SDs of 70%, 72% and 75%, four FITs of 12, 24, 36 h and 48 h. And the mechanical properties and its failure forms were investigated. The results show that: (1) The peak compressive strength of CTB decreases with the increases of filling interval. When the FIT is fixed, the UCS value increases along with the SD, and the peak compressive strength and filling interval are polynomial. (2) During the loading process, four stages of the compaction, line elastic, crack propagation and failure development are shown. With the extension of interval time, the failure forms of CTB may represent as the tension failure-shear failure transition-shear mixing damage. The conclusion can provide a useful reference for the strength design and stability control of CTB.