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深部黏土的埋深决定着深部黏土在进行人工冻结期间所承受的地压力的大小,而较大的地压力将会影响冻结壁形成时冻结温度的大小以及冻结壁的冷生构造,从而影响冻结壁的强度与稳定性。本研究通过对高压力作用下的深部黏土在不同含水率状态下进行冷却过程试验,分析了压力大小对不同饱和状态的深部黏土冷却曲线形式及初始结晶温度、冻结温度及过冷度的影响。结果表明:深部土的冻结温度、初始结晶温度以及过冷度都与土体所承受的压力密切相关。不论是非饱和状态、饱和状态还是过饱和状态下的深部黏土,其冻结温度都随土体所承受压力的增大而减小,而初始结晶温度则随压力的增大呈起伏状变化。利用物质结晶理论,进一步分析后认为冻结过程主要是自由孔隙水的相变过程;而压力作用会通过改变土体中土颗粒对孔隙水分子的吸附作用,改变土体中自由水的含量,进而改变土体冻结过程中潜热释放量的大小,最终影响土体冷生构造。
The depth of deep clay determines the magnitude of the ground pressure experienced by the deep clay during artificial freezing, and the larger ground pressure will affect the freezing temperature when the frozen wall is formed and the cold structure of the frozen wall, thus affecting the freezing. Wall strength and stability. In this study, the deep clay under high pressure was tested under different water cuts for cooling process. The effect of pressure on the shape of the cooling curve, the initial crystallization temperature, the freezing temperature and the degree of supercooling of the deep saturated clay was analyzed. The results show that the freezing temperature, initial crystallization temperature and degree of undercooling of deep soil are closely related to the pressure of soil. The freezing temperature of deep clays in the unsaturated, saturated or supersaturated state decreases with the increase of the pressure of the soil, while the initial crystallization temperature fluctuates with the increase of pressure. Using the material crystallization theory, it is further analyzed that the freezing process is mainly the phase change process of free pore water; and the pressure action will change the adsorption of pore water molecules in soil particles and change the content of free water in the soil. Changing the amount of latent heat released during soil freezing will ultimately affect the soil cold structure.