论文部分内容阅读
以硫酸盐渍土为研究对象,从理论上建立了冻结温度以上未相变含水率与温度的关系,并通过室内试验测试了硫酸盐土体及对应溶液中盐晶体初始析出温度和硫酸盐渍土未相变含水率在不同温度环境下的变化。从土体降温温度曲线、不同温度下核磁共振信号强度分析了温度对未相变含水率的影响。研究结果表明:在特定降温速率下,十水硫酸钠晶体析出存在滞后性,初始析出温度均低于其饱和浓度所对应的温度,并随着初始含盐量的减小,初始析出温度大幅度降低,且与土体比较,溶液中盐晶体易于析出;土体中十水硫酸钠晶体的析出造成含水率的减小明显大于溶液中晶体的析出引起的减小,且随着温度递降,未相变含水率递减;冻结温度以下,高含盐量的硫酸盐渍土未冻含水率与温度呈指数规律减小,-10℃以下,其含水率不再变化。对于低含盐量硫酸盐渍土,冻结温度以下其未冻含水率随温度降低同样按指数规律减小,且随着含盐量的增加,土体的含水率有所增加。
Taking sulphate saline soil as the research object, the relationship between the undistorted water content and temperature was established theoretically and the initial precipitation temperature and sulphate concentration of salt crystals in sulphate soils and corresponding solutions were tested by laboratory tests Changes of Soil Unconfined Water Content in Different Temperatures. The effect of temperature on the moisture content of un-transformed phase was analyzed from the cooling temperature curve of soil and the signal intensity of nuclear magnetic resonance at different temperatures. The results show that the precipitation of sodium sulfate decahydrate has a hysteresis at a specific cooling rate. The initial precipitation temperature is lower than the temperature corresponding to its saturation concentration. With the decrease of the initial salinity, And the salt crystals in the solution are easy to be precipitated compared with the soil. The precipitation of sodium sulfate decahydrate crystals in the soil leads to the decrease of water content obviously more than the decrease of the crystal precipitation in the solution, and as the temperature decreases, The water content of phase change decreases gradually; below the freezing temperature, the water content and the temperature of unfrozen water of sulpho-saline soil with high salinity decrease exponentially, and its moisture content no longer changes below -10 ℃. For low salinity sulphate soils, the unirrigated water content below the freezing temperature also decreased exponentially with decreasing temperature, and the soil moisture content increased with the salinity increasing.