饱气带区的渗流特性及地表模型

饱气带区的厚度和渗流特性随季节逐年发生变化,并伴随着吸力和含水量的变化,而这种变化紧密相关于地表影响因素和土体结构,如:阳光照射,降雨、温度、风速和风向等。笔者建立了一个表征地表和大气相互作用的力学模型,介绍了三种可能出现的地表和大气相互作用的情况,并对一些自然现象进行了分析和说明。在饱气带区的非饱和渗流特性的数值模拟过程中,提出了水的潜热系数和温度呈线性的关系,以及地表土体贮存能量和敏感热流成正比的假设,数值模拟结果和现场实测是较吻合的。同时,对饱气带区的变化规律进行了力学机理分析和解释。

Seepage properties of non-saturated soils in vadose zones and soil-surface model

The depth and seepage properties in the vadose zone are variable along the season change from one year to another, at the same time; the suction and water content are also changeable, the change comes from the influences of earth-surface and structural variation of soil mass, for instance: the irradiation of sun, the rainfall, the temperature, the speed and direction of the wind, the chemical action in soil mass, etc. In our paper, a mechanical model of earth-surface and atmosphere interaction is established; the three cases that occur possibly are presented, some natural phenomena are analyzed and explained. We proposed a linear function between the heat conductivity coefficient and temperature and assumed a proportional relation between the sensitive heat flux and the storage energy of soil in order to perform the numerical calculation. The numerical simulating results show a nearly agreement with the in situ measuring data. The mechanical mechanism in vadose zone is also discussed and studied.