包气带的水分分布特征及给水度的探讨

FEATURE OF THE MOISTURE DISTRIBUTION IN AERATION ZONE AND SPECIFIC YIELD

文中用不等径的葫芦状毛管网络模型讨论了均质土的重力释水机制,认为重力释水与变动后的潜水位以上原饱水带及与其相联系的支持毛细水带有关;据此定义了给水度。 均质土给水度的大小与重力释水前后包气带的水分分布特征有关。由模型的分析说明,蒸发条件下的初始水分分布特征曲线偏低,造成均质土的重力释水减量,使给水度变小。

The paper discusses the mechanism of dewatering in the homogeneous and isotro-pic soil under gravity following the model of calabash network for unequal diameter. It is held that gravitational dewatering takes place in the originally saturated zone above the water table at the time after f luctua tion,and is related to the capill-,ary fringe for this reason,the specif ic yield is redefined.The specific yield of homogeneous and isotropic soil is related to the feature of moisture content distribution in the aeration zone before and after gravitational de-watering. It is shown from the analysis of the model that the characteristic curves of original moisture distribution under evaporation is lower than that disevaporat-on this causes the amount of gravitational dewatering in homogeneous and isotropic soil, to decrease,and so does the specific yield.