地下气化煤层软岩顶板相似材料研究

Study on Similar Material of Soft Rock Roof for Underground Coal Gasification

为了寻找适合煤炭地下气化模型实验软岩顶板的相似材料种类及材料配比,通过岩石力学性质实验获得现场顶板软岩的相关力学参数,并根据相似原理理论,以河砂为骨料、粘土和石膏为胶结物,利用正交实验和全面实验方法分析了不同材料配比下的单轴抗压强度,并与利用相似原理处理的抗压强度进行对比研究,结果表明:石膏对相似材料抗压强度的影响作用显著,且受热易粉化,不适合作为煤炭地下气化模型实验软岩顶板相似材料的胶结物;以河砂和粘土为相似材料原料时,当两者质量比为3∶1时,通过实验测得的单轴抗压强度与经过理论计算获得的抗压强度吻合,可满足模型实验对煤层软岩顶板的力学要求。

To explore the optimal similar materials and the proportion for soft rock roof in underground coal gasification （UCG） model test, the mechanical parameters of a field soft roof were obtained by rock mechanics property experiment. Based on similarity principle, river sand was selected as aggregate, clay and gypsum as cement. Orthogonal experiment and comprehensive experiment was carried out to analyze the uniaxial strength variation of roof sample under different materials proportions, which was compared with that processed by similarity principle. The results show that, gypsum can t serve as cement for soft rock roof in UCG model experiment, the influence of which is obvious on the strength of similar materials, and is prone to be pulverized under high temperature. While river sand and clay are selected as raw materials with a mass ratio of 3 ： 1 （ river sand ： clay）, the uniaxial strength of similar materials is consistent with the uniaxial strength calculated based on similarity principle, and the mechanical requirements of soft roof is satisfied for UCG model experiment.