湿排粉煤灰似膏体充填采空区试验研究

Experiment with filling the stope area with the wet paste-like fly ash material

为了确定湿排粉煤灰似膏体充填的关键技术参数,通过湿排粉煤灰物理化学试验、膏体充填配比试验及现场工业试验,研究了湿排粉煤灰的物理化学特性、膏体充填配比参数和工业试验运行参数。结果表明,湿排粉煤灰松散干密度为0.85 g/cm3,管道输送性能良好,渗透系数为8.52×10-4,脱滤水较困难,单位沉降量与压力关系曲线比较平缓,凝固后沉缩率较低,含有一定量的活性SiO2和Al2O3成分,具有一定的胶凝特性。当m（水泥）∶m（粉煤灰）=1∶8-1∶10、质量分数为62%-65%时,初凝时间180 min,28 d强度大于1 MPa,现场工业试验历时45 min,充填质量分数稳定在60%-64.5%,充填系统运行平稳,初期强度达到工业要求。湿灰作为似膏体充填骨料在华泰矿业首次得到成功应用,充填材料成本为50-57元/t。

This paper intends to introduce a novel approach to using wet tly ash as a new filling aggregate to the stope filling. For this purpose, we have done physical and chemical experiments to test and measure the key technical parameters of wet fly ash paste-like filling materials. According to the experiment results, we have drawn three conclusions： （1） The wet ash has nice pipeline transmission and topcontacted properties; （2） The wet fly ash contains a certain amount of active ingredients such as SiO2 and AI2 03, so it has potential gelling property; （3） As a retarder used in industry, the early strength of wet fly ash is lower than the later strength. Based on the physical and chemical experiment results, We have carried out a fill- ing ratio combining experiment of wet fly ash paste-like. The experiment results indicate that the best technical parameters that the mass ratio between the cement and the fly ash tends to be from 1 ： 8 to 1 ： 10 with the mass concentration being 62 % to 65 % . Under such conditions, the initial setting time of the specimen is less than three hours, however, the time can be de-molded on the next day. Moreover, the 28 days strength of the specimen proves to be 1.48 MPa. The bleeding rate of the paste filling turns out to be about 5 % . When the consolidation was done with backfill, there was no obvious creep phenomenon, neither with the rib spalling nor subsidence phenomenon for the fly ash paste-like mixture with the cement. Besides, on basis of the filling ratio combination experiment, we have also made an onspot industrial experiment, in which the filling system has been found going on quite smoothly. And, in turn, the filling mass concentration has been made stabilized at the percentage of 60% - 64.5% , thus, the initial strength proves to come up to the industrial demands. After the on-site industrial test, we have proceeded with the normal filling mining work and successfully replaced the security pillar in the mining area. The cost of the filling materials （besides the water used） of wet ash paste-like material is only 67 - 75 yuan/m3.