考虑薄膜水的利用介质粒度分布获取水土特征曲线的方法

Predicting the soil-water characteristic curve from soil particle size distribution considering the film water

  • 摘要: 利用介质粒度分布间接获取水土特征曲线(SWCC)是一种快速、经济的方法。由于该方法的传统模型(HP模型和MV模型)忽略了薄膜水,获得的SWCC在低含水率段存在显著误差。提出了一种考虑介质表面薄膜水的含水率估算方法,与HP模型和MV模型的吸力计算方法结合预测SWCC,选用土壤水力性质数据库UNSODA的17种土壤样品对两种修正模型的预测效果进行了验证。结果表明,采用薄膜水修正后的HP模型和MV模型可以显著改善传统模型中SWCC低含水率段含水率的低估,并能有效地预测砂土等粗粒介质的SWCC。另外,含水率估算中引入参数β后,修正的MV模型也可用于壤土和黏土等细粒介质的SWCC的预测。

     

    Abstract: Predicting soil water characteristic curve (SWCC) from particle size distribution was an easy, rapid and economical method. However, the traditional estimate of water content in this method didn't consider the adsorbed water films, which led to an underestimate of water content in the dry range of the SWCC. In this study, a modified method was developed to take the film water into account when estimating water content, and subsequently the SWCC was predicted by combining water content with the matric suction which estimated by the method in HP model and MV model. The modified model was tested on seventeen soil samples, selected from the UNSODA database. The results illustrated that the modified model significantly improved the model performance in the dry range of the SWCC and accurately estimated the SWCC of sand. Furthermore, the modified model was also applicable for loam and clay by introducing a parameter β.

     

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