植被发育斜坡土体非饱和渗透特性的预测方法

非饱和渗透系数对评价非饱和土体的性质具有重要意义,尤其是对灾害频发的植被发育斜坡。然而现场试验或室内试验测量非饱和渗透系数耗费时间多,对试验设备要求高,为非饱和土体的渗透性研究带来很多不便。本文在对Brooks-Corey模型进一步推导的基础上,利用Bloemen提出的孔径分布参数计算方法来推求土体的非饱和渗透系数,只需获得土体颗粒组成、有机质含量、饱和渗透系数及重量含水量,就可以计算得到非饱和渗透系数的预测值,这样就提高了非饱和渗透系数的计算效率。同时,通过比较模型计算结果与HYDRUS-2D计算值,得知此方法应用于植被发育斜坡土体是可行的,而且有较高的精度,并提出了进一步的优化方向。

A method of predicting unsaturated hydraulic conductivity in well vegetated slope soils

Unsaturated hydraulic conductivity is significant for evaluating properties of unsaturated soils, particularly for unsaturated soils of well vegetated slope. However that time consuming and high requirements on equipments of using field and laboratory approaches brings a lot of difficulties for the study on unsaturated hydraulic conductivity. A relative simply method, which derived from Brooks-Corey model, is described in this paper for estimating the unsaturated hydraulic conductivity. By this mean unsaturated hydraulic conductivity be calculated from saturated hydraulic conductivity, gravimetric water content and the pore size distribution exponent which estimated by Bloemen＇ s equation from organic matter content and granular composition. This could improve the computational efficiency. With comparing the model results and the HYDRUS-2D calculated value, this method is proved that it has high relative precision and is applicable to well vegetated slope soils. Furthermore, the direction of further optimization is put forward in this paper.