为了定量研究由蒙脱土和聚丙烯酰胺制备而成的渗灌复合材料导水特性与其组分之间及土壤湿度的关系，该文利用混合高斯模型模拟求解渗灌复合材料的平衡导水率、材料组分比例及土壤湿度之间的关系。设置9组组分比例不同（蒙脱土与聚丙烯酰胺质量比5～25）的渗灌复合材料在8个土壤湿度（土壤质量含水率3%～17%）下进行建模，另外2组（（蒙脱土与聚丙烯酰胺质量比8和18）不同的组分制备而成复合材料在2组不同土壤湿度（土壤质量含水率4%和14%）下进行验证。结果表明：建立的渗灌复合材料平衡导水率与材料组分的关系函数，相应模拟值与实测值之间的均方根误差（root mean squared error，RMSE）≤25.87 g/h，误差平方和（sum of squares of error，SSE）≤160，决定系数（coefficient of multiple determination，R2）≥0.8933，利用混合高斯模型模拟平衡导水率、材料组分关系函数的相关参数与土壤湿度之间的关系，相应模拟值与实测值之间的RMSE≤195 g/h，SSE≤98350，决定系数R2≥0.6868，说明利用混合高斯模型拟合渗灌复合材料的平衡导水率、材料组分比例及土壤湿度之间的关系函数具有很好的稳定性、可行性及精确性；经验证，平衡导水率、材料组分比例及土壤湿度关系函数的模拟值与实测值之间的最大相对误差为14.14%，表明用该函数模拟渗灌复合材料H-C-M之间关系的可靠性。该研究对于后续的渗灌材料的研制及应用具有指导意义。%Infiltration irrigation is a promising water-saving technique. The characteristics of infiltration irrigation material greatly affect the water use efficiency. However, little studies have focused on the material components and hydraulic conductivity. This paper was aimed at acquiring the quantitative self-adjusting water-conduction characteristics of infiltrating irrigation material (composed by montmorillonite MMT and polyacrylamide PAM) with its components and soil moisture. The Gaussian mixture model was used to simulate and calculate the relationship function of balance hydraulic conductivity of infiltrating irrigation material, component proportion and soil moisture. Infiltrating irrigation materials with 9 different ratios of components(MMT:PAM =5:1, 7.5:1, 10:1, 12.5:1, 15:1, 17.5:1, 20:1, 22.5:1, 25:1) were prepared. The material was ovendried and condensed into solid and then ground into power≥37µm, weighed into a glass tube (diameter in 5 mm and height in 200 mm) with both ends fixed with degreasing cotton for tests. The glass tube was marked with scales. The experiment was conducted in a laboratory under different soil moisture conditions (3%, 5%, 7%, 5%, 11%, 13%, 15%, and 13%). The glass tube filled with material was immersed into soils with different moisture. There was enough water in the glass tube for water supply. The dry weight of soil placed in a beaker was about 250 g. The beakers were put into an artificial climate box with the humidity and temperature of 50% and 25℃ to ensure that the soil environment did not change with the environment outside during the experiment. Water height was recorded every 2 h when the water-conductivity balance state was reached after 24 h. The data were used for establishing modes describing conductivity, components and soil moisture relationship. In addition, another materials with different component ratios (MMT:PAM=8 and 18) under 2 different soil moisture(4% and 14%) were applied for model validation. There was a total of 72 experimental points for model establishment. The Gaussian mixture model was fitted using MATLAB toolbox cftool. The results showed that the relationship between hydraulic conductivity and component ratios under different soil moisture could well fitted by Gaussian mixture model with the determination coefficient higher than 0.9 and the root mean square of error (RMSE) of 4.981-25.87 g/h. Obvious peaks were present in the fitness curves, which may reflect the interaction of material itself and soil moisture. On water balance, the material was of even swelling structure, which facilitated water conduction in materials and thus led to peaks of hydraulic conductivity. From the fitness, the model parameters could be obtained and these parameters had good exponential relationship with soil moistures with determination coefficient about 0.9 and RMSE smaller than 195 g/h. When those parameter values were used for validation, the relative errors of measured and predicted hydraulic conductivity were 0-14.14%, less than 20%. It indicated the Gaussian mixture model could well describe the relationship between hydraulic conductivity of infiltrating irrigation material, material composition and soil moisture. However, the results need to be validated in field and more studies on influential factors of hydraulic conductivity of infiltrating irrigation material should be carried out. This study has a guiding role on subsequent infiltrating irrigation material preparation and application.
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