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潜水蒸发是塔克拉玛干沙漠地区浅层地下水的主要消耗项.潜水极限蒸发强度是在给定的土壤和潜水埋深条件下单位时间内土壤最大可能输送到地表的水量,是建立潜水蒸发计算模型的重要参数和控制条件.利用实测的土壤含水率和土壤水吸力数据,根据Van Genuchten提出的水分特征曲线公式,采用最小二乘法拟合了塔克拉玛干沙漠地区土壤的水分特征曲线方程.采用瞬时剖面法现场测定了非饱和土壤导水率,建立了该区非饱和土壤导水率的计算公式.在对非饱和土壤导水率的计算公式进行概化的基础上,根据非饱和土壤水稳定流理论,推导出计算潜水极限蒸发强度的准解析解.研究结果表明:采用Van Genuchten提出的水分特征曲线公式描述塔克拉玛干沙漠地区土壤水分特性,效果较好;潜水极限蒸发强度随潜水埋深的增大而呈幂函数关系递减.
Submersible evaporation is a major contributor to the shallow groundwater in the Taklamakan Desert, where the ultimate evapotranspiration is the maximum amount of soil that can be transported to the surface per unit of time for a given soil and submerged depth, which is an important factor in establishing a model for calculating subductional evaporation Parameters and control conditions.Using the measured soil moisture content and soil water suction data, according to the formula of water characteristic curve proposed by Van Genuchten, the least square method was used to fit the soil water characteristic curve equation in the Taklimakan Desert. The unsaturated soil hydraulic conductivity was established and the formula for calculating the hydraulic conductivity of unsaturated soil in this area was established.On the basis of generalizing the calculation formula of hydraulic conductivity of unsaturated soil and according to the steady flow theory of unsaturated soil water The results of quasi-analytic solution of calculating the ultimate evapotranspiration of the submarine are given.The results show that the characteristic of soil moisture in the Taklamakan desert is described by the formula of water characteristic curve proposed by Van Genuchten, and the effect is better. The ultimate evapotranspiration of the submarine reaches the power exponentially with the increase of the submerged depth Decreasing function.