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为研究岩石在低温环境下内部温度场随冻结、融化过程变化特征,探讨岩石在冻融循环过程中整体热传导规律。现开展干燥、饱水状态下类砂岩试样冻融循环室内试验,分析类砂岩试样在冻结、融化过程中内部非等温传递规律;结合试验现象,从水冰微观结构探讨水冰相变过程产生的热传导弛豫机制;最后,基于热传导理论,详细探讨冻融循环干燥、饱水状态下岩石热传导方程,给出饱水岩石三阶段温度分布理论解,并通过与试验对比,验证理论分析的合理性。研究结果表明:(1)冻融循环过程中干燥状态下的类砂岩试样,其温变曲线大体呈现负指数曲线特征,且越靠近边界面,温变速率越大,同时相对冻结过程,融化升温过程速率更快;(2)冻融循环过程中饱水状态下的类砂岩试样,其温变曲线呈现明显的三区段过程,在水冰相变过程产生典型的缓温变段,且相对干燥状态,其温变速率均出现一定程度降低;(3)利用水分子相变过程中微观结构变化,可较好地解释水冰相变过程造成的热传导弛豫现象;(4)给出了干燥、饱水状态下岩石热传导方程,并借此探讨了饱水状态下固相、液相及相变区温度理论解,通过与室内试验对比,验证了理论分析公式的合理性。研究对认识冻融环境下岩石内部温度场演化规律具有一定参考价值。
In order to study the variation of internal temperature field with the freezing and thawing process of rock at low temperature, the overall heat conduction law of rock during the freeze-thaw cycle was discussed. Now dry and saturated sandstone-like samples freeze-thaw cycle laboratory tests to analyze the type of sandstone samples in the freezing and thawing process internal non-isothermal transfer law; combined with the test phenomenon, from the microscopic structure of water ice ice-water phase transition process Finally, based on the theory of heat conduction, the heat conduction equation of rock under freeze-thaw cycle and saturated water condition is discussed in detail. The theoretical solution of the three-stage temperature distribution of saturated water rock is given. Compared with the experimental results, the theoretical analysis rationality. The results show that: (1) The sandstone samples in the dry state during the freeze-thaw cycles have a generally negative exponential curve, and the closer to the boundary surface, the larger the temperature-dependent rate and the relative freezing and melting (2) Sand-like samples in saturated water during the freeze-thaw cycles show a clear three-stage temperature-dependent curve, producing a typical slowly changing section during the ice-water phase transition (3) The thermal conductivity relaxation caused by water-ice phase transition can be well explained by the change of microstructure during the phase transition of water molecule; (4) The equations of rock heat conduction under dry and saturated water conditions are discussed. The theoretic solution of temperature, solid phase, liquid phase and phase transition zone in saturated water are discussed. The rationality of theoretical analysis formula is verified by comparison with laboratory tests. The research has some reference value to understand the evolution law of temperature field inside rock in freezing and thawing environment.