基于响应面法的煤矸石胶结充填体抗压强度试验研究

煤矸石胶结充填可有效控制煤矿开采造成的地表沉陷，减少环境破坏。为研究细矸率、水泥掺量和料浆质量浓度对充填体抗压强度的影响规律，优化充填材料配比，在单因素试验基础上采用响应面法设计3因素17组配比试验，构建响应面回归模型并计算优化配比，为工程上获得合理充填材料配比提供科学方法。研究表明:单因素对充填体抗压强度的影响大小依次为料浆质量浓度、水泥掺量、细矸率；细矸率和料浆质量浓度交互作用对充填体早期抗压强度影响较小，水泥掺量和料浆质量浓度交互作用对充填体中后期抗压强度影响最大；为满足充填强度要求（一般≥5.0 MPa），经模型优化确定充填料浆最佳配比为m（煤矸石）︰m（粉煤灰）︰m（水泥）︰m（水）=50%︰22%︰8%︰20%，细矸率为52%时，充填体28 d抗压强度为5.07 MPa，验证试验误差范围在2%左右，模型精准可靠；水泥水化生成Ca(OH)₂激发粉煤灰和煤矸石活性物质生成钙矾石（AFt）和水化硅酸钙（C-S-H）凝胶，随着龄期不断增长对胶凝体系起到了良好的连接作用，网状结构更加稳定，能有效提高充填体抗压强度。 

Experimental Study on Compressive Strength of Coal Gangue Cemented Backfill Based on Response Surface Method

Ground subsidence caused by coal mining could be sufficiently controlled using cemented coal gangue backfilling materials. In order to study the influence of fine gangue rate, cement content and mass concentration of slurry on the compressive strength of backfilling materials and optimize mixture ratio of backfilling materials. Response surface method was used to design an experiment with 3 factors and 17 proportions based on the single factor experiment, furthermore, the response surface regression model was constructed, and the optimal ratio was calculated, which could provide a scientific method for obtaining a reasonable proportion of filling materials in industry. The results showed that the influence of single factor on the compressive strength of backfilling materials was in order of mass concentration of slurry, cement content and fine gangue rate. The influence of interactions between fine gangue rate and mass concentration of slurry on compressive strength of backfilling materials in the early stage was slight, while the influence of interactions between cement content and mass concentration of slurry on compressive strength of backfilling materials in the middle and later stages was the greatest. The optimal ratio of backfilling slurry was determined by the results of model optimization as m (coal gangue)∶m (fly ash)∶m (cement)∶m (water) = 50%∶22%∶8%∶20%, and the fine gangue rate was 52%, The compressive strength of backfilling materials curing for 28 days was 5.07 MPa, and the error range of the verification test was about 2%, the model was accurate and reliable. The Ca(OH)₂ generated by cement hydration motivates the active substances of fly ash and coal gangue and generates ettringite (AFt) and calcium silicate hydrate (C-S-H) gels. The continuous growth of curing age plays a good role in connecting the cementing system, making the network structure more stable and effectively improving the compressive strength of backfill.