土体水分蒸发模型研究进展

Review on Soil Moisture Evaporation Model

土体水分蒸发是土体-大气物质和能量交换的主要过程之一,对土体的工程性质有重要影响。尤其是近些年来,受全球气候变化影响,极端干旱性气候频繁发生,与蒸发相关的岩土和地质工程问题越来越突出,逐渐成为国际研究的热点。建立土体水分蒸发模型是该课题研究的首要目标,对准确评估和预测气候作用下土体水分场信息有重要理论和现实意义。着重对国内外学者近几十年来围绕土体水分蒸发模型所取得的研究成果进行了归纳和总结,依据各种模型的理论基础进行了分类,总体上可分为表面能量平衡模型、水量平衡模型、质量传输模型、阻力模型、温度-风速模型及吸力模型等六大类别。在此基础上,分别阐述了各类模型的研究进展,并对其中一些代表性模型进行了详细介绍,对比分析了各个模型之间的联系与区别,并探讨了它们的优缺点和适应条件。总体而言,现有的模型存在重气象因素而轻土性因素的特点,对砂土和饱和土具有较好的适应性,而对黏性土和非饱和土的适应性较差。基于此,结合本学科的特色和研究背景,提出了今后该课题的研究重点,包括非饱和土的蒸发模型问题研究、黏性土水分蒸发模型研究、考虑土体裂隙参数的土体水分蒸发模型研究、构建通用型的土体水分蒸发模型等几个方面。

Evaporation of water is one of the major processes of mass and energy exchange between soil and atmosphere. It can significantly influence soil engineering properties. Especially, due to the global climate change in recent years, extreme drought events occur in increasing frequency. The geotechnical and geological engineering problems related to evaporation are becoming more and more prominent. A growing number of scholars are working on this issue. First of all, it is necessary to build a model of water evaporation in soil. Based on the model, one can then assess and forecast the water field information under the influence of climate. According to the published research results all over the world in recent decades, the models related to soil water evaporation were summarized and categorized in this paper. According to the theoretical bases, these models can be separated into six categories, surface energy balance model, water balance model, mass transfer model, resistance model, temperature-wind speed model and suction model. The research progress of each kind of model was introduced. The details of some representative models were presented. The relations and differences between these models, and their advantages, disadvantages and application conditions were discussed. Generally, the existing models paid more attention to meteorological factors rather than soil nature factors. As a result, they can be only applied to saturated sandy soil but not to unsaturated clayey soil. For this reason, some important research topics that should be well investigated in the future were proposed by considering the characteristics of this discipline and research background, including the evaporation model of unsaturated soil, clayey soil, cracked soil and the establishment of general evaporation model for different soils.