包气带土壤水分滞留特征研究

Study on water hysteresis in aerated soil

在水资源开发利用与水环境保护方面， 包气带土壤水分滞留曲线非常重要． 本文在Ｖａｎ 经验公式基础上，建立了吸湿与脱湿曲线， 将最小二乘法与非线性单纯形法相结合， 确定了４ 个待求参数的获取方法； 并探索了滞留曲线在数值模拟中的使用． 用现场试验资料检验了求包气带土壤水分特征参数方法的有效性， 同时对４ 种土质的脱湿与吸湿试验进行了模拟计算． 结果表明： 本文采用的求水分滞留曲线的方法快捷、方便， 对试验数据的模拟较好．

Water hysteresis in aerated zone of soil is significant to the development and utlization of water resources as well as the protection of water environment.Based on the empirical Van equation,the imbibition and drainage curves are estabilished.An algorithm to acquire 4 unknown parameters is developed by means of coupling the least square method and nonlinear simplex method,and the application of the hysteresis curve to numerical simulation is discussed.Furthermore,the method to calculate the water characteristic curves in aerated zone are verified by in\|situ data,and the modeling for imbibition and drainage test in 4 kinds of soil with different characteristics is performed.The results show that the algorithm to acquire the water characteristic curves adopted in this paper is convenient to use and possesses good fitting effect to test data.