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为掌握我国西部白垩系富水基岩的热物理特性,采用基于瞬态平面热源技术的Hot-Disk热常数分析仪对不同温度(-30℃、-20℃、-10℃、-5℃、0℃、10℃、27℃)、不同含水(干燥、微量含水、大量含水、饱水)、不同粒径(中粒、粗粒)白垩系砂岩的热导率λ进行了测试。结果表明:饱水砂岩热导率λ随温度降低而先增大后略有减小并趋于稳定,-10℃时达峰值3.375 W/m·K;砂岩热导率λ随含水率ω增加呈先增大后减小趋势,λ的范围在0.368-2.242 W/m·K之间,当ω=6.282%-7.539%时热导率λ较大,此时中砂岩最大热导率可达2.242 W/m·K;常温下,相同含水的非饱和白垩系粗砂岩热导率总大于中砂岩0.254~0.284W/m·K,其中粗、中砂岩平均孔隙度分别为15.169%、21.863%,说明非饱和时砂岩孔隙度越小、颗粒粒径越大则热导率越大。可为西部白垩系地层深厚富水基岩煤矿立井冻结设计提供科学的理论依据。
In order to understand the thermophysical properties of Cretaceous water-rich bedrock in western China, Hot-Disk thermal constant analyzer based on transient planar heat source was used to measure the thermal physical properties of Cretaceous water-rich bedrock at different temperatures (-30 ℃, -20 ℃, -10 ℃, -5 ℃, 0 ℃, 10 ℃, 27 ℃), and the thermal conductivity λ of Cretaceous sandstones with different water contents (dry, trace water, abundant water and saturated water) and different grain sizes (medium grain and coarse grain) were tested. The results show that the thermal conductivity λ of saturated sandstone increases first and then decreases slightly and tends to be stable, reaching the peak value of 3.375 W / m · K at -10 ℃. The thermal conductivity λ of sandstone increases with the increase of water content ω The first increases and then decreases, the range of λ is between 0.368-2.242 W / m · K, the thermal conductivity λ is larger when ω = 6.282% -7.539%, and the maximum thermal conductivity of sandstone reaches up to this time 2.242 W / m · K. At room temperature, the thermal conductivity of the intact unsaturated Cretaceous coarse sandstone with the same water content is larger than that of the middle sandstone by 0.254 ~ 0.284W / m · K. The average porosity of the coarse and middle sandstones are 15.169% and 21.863% , Indicating that the smaller the porosity of sandstone is, the larger the particle size is, the larger the thermal conductivity is. It can provide a scientific theoretical basis for the freezing design of deep well water-rich rock coal mine shaft in the western Cretaceous.