Hong Zi-Jie, Chen Shun, Li Zhen-Hua, Chen Zhi-Xuan, Cui Xu, Xu Lei
School of Civil Engineering, Henan Polytechnic University, Jiaozuo, 454003, China.
The project of Henan Key Laboratory of Underground Engineering and Disaster Prevention (Henan Polytechnic University), Jiaozuo, China.
PLoS One. 2023 Sep 29;18(9):e0291519. doi: 10.1371/journal.pone.0291519. eCollection 2023.
This paper aims to analyze the roof stability when the reclaimed working face passes through abandoned roadway. The mechanical model of main roof in abandoned roadway was established for the purpose of theoretical analyses. To ensure the stability of the abandoned roadway, the strength formula of backfill body was deduced. The optimum ratios among different compositions of the filling material were determined by experiment, while the viscosity, bleeding, hydration temperature and compressive strength of filling material were also studied. Test results indicated that the optimum ratio among coal ash, lime and compound activator is 80:15:5, and the ideal water cement ratio is 0.7:1. It was also found that no bleeding occurred, the rheological behavior of slurry presented shear thinning fluid and the hydration temperature of filling body was relatively stable which is mainly maintained at 40°C. The uniaxial compressive strength of filling material with 28 and 90 days curing were 3.35 and 6.62 MPa respectively. Under a confining pressure environment, the filling material presented an obviously plastic deformation. Field test showed that the filling rate was almost 100%, when working face passed through abandoned roadway, the surface of filled body was complete and no roof collapse was triggered. Therefore, a better bonding effect was proved for the filling body.
本文旨在分析复垦工作面通过废弃巷道时的顶板稳定性。为进行理论分析，建立了废弃巷道中老顶的力学模型。为确保废弃巷道的稳定性，推导了充填体的强度公式。通过试验确定了充填材料不同组分之间的最佳配比，同时还研究了充填材料的粘度、泌水、水化温度和抗压强度。试验结果表明，粉煤灰、石灰和复合激发剂的最佳配比为80:15:5，理想水灰比为0.7:1。还发现未出现泌水现象，料浆的流变行为呈现剪切稀化流体，充填体的水化温度相对稳定，主要维持在40℃。养护28天和90天的充填材料单轴抗压强度分别为3.35MPa和6.62MPa。在围压环境下，充填材料呈现明显的塑性变形。现场试验表明，充填率几乎达到100%，工作面通过废弃巷道时，充填体表面完整，未引发顶板垮塌。因此，证明了充填体具有较好的粘结效果。
