非饱和黄土水分蒸发温度效应试验研究

Experimental Study on Temperature Effect of Water Evaporation in Unsaturated Loess

为进一步掌握西北干旱地区非饱和黄土水分蒸发规律,进行不同环境温度下非饱和黄土水分室内模拟蒸发试验,探讨蒸发过程中土体含水率变化、温度对蒸发速率及累计蒸发量的影响。结果表明:随蒸发时间的延长,土体含水率日改变率逐渐减小;环境温度对土体含水率的影响与土体深度范围、蒸发时段均有关,相同的升温值导致土体含水率的变化量是不相等的,不同的温度范围内土体含水率敏感变化深度不同;环境温度与室温接近时,土体每天的蒸发速率随时间延长没有明显变化,但当环境温度高于室温一定值时,土体每天蒸发速率随时间呈递减状态;环境温度一定时,气候模拟箱自身的冷凝作用使得非饱和土体累计蒸发量随蒸发时长呈波动增加趋势。

In order to further understand the law of water evaporation of unsaturated loess in the arid area of Northwest China. Based on the indoor model test, the water evaporation experiments of unsaturated loess under different ambient temperatures were carried out. The effects of soil moisture content and temperature on evaporation rate and cumulative evaporation were discussed. The results show that with the extension of evaporation time, the diurnal change of soil moisture content is decreased gradually. The influence of environmental temperature to the soil moisture content is related with the depth range of soil sample, evaporation stage and reference temperature. The same temperature increase results in different moisture changes, and different temperature ranges correspond to different depth ranges in which the soil moisture content is changed sensitively. When the environmental temperature is close to the indoor temperature, the evaporation rate develops with time without obvious fluctuation, but the evaporation rate is fluctuated and decreased with time obviously when the environmental temperature is higher than the indoor temperature to a certain extent.