采空区超细粉煤灰注浆充填材料正交试验及回归分析

注浆法处理煤矿采空区,浆材的选择至关重要。通过正交试验的方法,测试大掺量超细粉煤灰条件下水泥粉煤灰注浆材料的各项物理力学性能,讨论了不同水固比、固相比、水玻璃掺量对浆液凝结时间、析水率、结石率以及不同龄期无侧限抗压强度的影响。结果表明:水固比对浆材各项性能的影响最为显著,固相比其次,水玻璃掺量最小;各配比浆液结石体28 d的抗压强度一般＞1 MPa,且后期强度仍持续增长,90 d强度较28 d强度提高了60%以上。通过曲线拟合的方法,得出抗压强度随配比的回归公式和随龄期的预测公式,为工程注浆施工提供参考依据。

Orthogonal Experiment and Regression Analysis on Ultra-fine Fly AshGrouting Material for Teating Coal Mine Goaf

Grouting material is of crucial importance for the treatment of coal mine goaf by grouting. The physical and mechanical properties of fly ash cement grouting material with large volume ultra-fine fly ash are tested through orthogonal experiment. The influences of water-solid ratio, solid phase ratio, and dosage of sodium silicate on the setting time, water separating proportion, concretion rate, and unconfined compressive strength at different ages are also examined.Results showed that the performance of the slurry material is significantly affected by water-solid ratio, followed by solid phase ratio and dosage of sodium silicate. The 28-day compressive strength of grouting slurry with varying mix ratio is generally higher than 1 MPa and continues to grow; the strength at the 90^th day is larger than that at the 28^th day by over 60%. The regression formula of compressive strength along with mix proportion and the predictor formula of compressive strength along with age are obtained by curve fitting.