深热井巷热害隔离材料复配体系及性能研究

Study on Combined System and Performance of the Thermal Insulation Material Applying to High Temperature Strata Tunnel in Deep Coalmine

本工作针对深热矿井掘进巷道围岩放热作为主要热源之一导致的井巷高温热害问题,提出延缓或者限制高温围岩向井巷传热的“主动阻/隔热”以实现源头治理热害的研究构想。基于矿山热害学和传热传质学,结合实际巷道的围岩岩性、风流参数等,计算结果证明采用低导热系数的热害隔离材料达到“主动阻/隔热”的理论可行性。运用混凝土学和胶体化学等知识,遴选和自配了热害隔离材料的胶凝材料、骨料、掺和料和外加剂。基于正交试验、实验测试和功效系数分析,获得了热害隔离材料的综合性能最优配比,即粉煤灰用量为水泥的30%(质量分数,下同),可再分散性乳胶粉和聚丙烯纤维掺量分别为胶凝材料的0.5%和0.4%,水灰比为0.6。通过黑红二值化处理和扫描电镜分析发现,最优配比下热害隔离材料的内部微孔密集,分布均匀,且为互不联通的闭孔结构,其数量远大于其他配比。研制出的新型井巷热害隔离材料,其关键性能参数:干密度为602.7 kg/m^(3),抗压强度为2.58 MPa,导热系数为0.1937 W/(m·K),导热系数仅为普通混凝土的0.1133倍,满足井巷高温围岩隔热要求,因此该材料具有广泛应用价值。

Aiming at the problem of high temperature heat damage caused by the surrounding rock of the tunnel in deep-hot mine excavation as one of the main heat sources, the active heat resistance/insulation method that delays or restricts the heat transfer of the high temperature surrounding rock to the mine tunnel is proposed to achieve source control of heat damage research conception. Based on the mine thermal damage and heat and mass transfer theory, combined with the surrounding rock lithology and air flow parameters of the actual tunnel, the calculations proved the theoretical feasibility of using low thermal conductivity thermal insulation materials to achieve active resistance and heat insulation. Using the knowledge of concrete science and colloidal chemistry, the cementitious materials, aggregates, admixtures and admixtures of heat damage isolation materials were selected and self-matched. Based on the orthogonal test, experimental test and efficiency coefficient analysis, the optimal ratio of the comprehensive performance of heat damage isolation material is obtained. That is, the dosage of fly ash is 30% of the cement, the dosage of redispersible latex powder and polypropylene fiber are 0.5% and 0.4% of cementitious material respectively, and the water-cement ratio is 0.6. Through black-red binarization treatment and scanning electron microscope analysis, it was found that the internal micropores of the thermal insulation material with the optimal ratio were dense and evenly distributed, and they were unconnected closed-pore structure, the number of which was much larger than other ratios. The key performance parameters of the new type of mine tunnel thermal insulation material are as follows: dry density is 602.7 kg/m^(3), compressive strength is 2.58 MPa, thermal conductivity is 0.193 7 W/(m·K), thermal conductivity is only 0.113 3 times of ordinary concrete, which basically meets the thermal insulation requirements of high-temperature surrounding rock in mines, and has a wide range of application values.