中文摘要：

崩岗是我国南方花岗岩地区破坏性极强的水土流失类型。以鄂东南地区两个典型的崩岗剖面为对象,探讨崩岗剖面包括表土层、红土层、斑纹层和碎屑层的土壤水分特征及方程拟合过程,明确崩岗发生的水分运动机理。结果表明：崩岗土壤释水量伴随吸力呈规律性变化,其中斑纹层和砂土层低吸力时脱水能力大于表土层和红土层,高吸力时各个层次土壤水分特征曲线趋于平缓。利用当量孔隙的计算发现不同土层的孔隙变化也存在变化规律,均体现为由表土层至碎屑层土壤大孔隙比例增加而毛管孔隙减少。选取van Genuchten方程和Gardner方程对崩岗剖面土壤实测数据进行了曲线拟合,同时进行了两个方程的拟合评价,R2基本在0.9以上,同时残差平方和的数量级在10-3和10-5之间。研究表明,van Genuchten方程参数能够较好地拟合崩岗表土层和红土层土壤水分特征曲线的实测数据,误差相对较小,而Gardner方程适用于斑纹层和碎屑层土壤。

英文摘要：

Collapse mound,a serious soil erosion phenomenon in granite areas of South China,occurs mainly on mound or hill slopes under the interaction of water and gravity,causing severe destructions and threats in a wide range,including Hubei,Hunan,Jiangxi,Anhui,Fujian,Guangdong,and Guangxi,mainly south to the Yangtze River,and hence a grave impact on the economy in these hilly regions. So far a lot of research work has been done on mechanisms of how mount collapses occur. In the aspect of water regime in collapse mounds,related scientists have analyzed permeability of the colluvial deposits from collapse mounds,revealing that colluvial soil reaches the level of steady permeation in a relatively short time,and also studied soil permeability of collapse mounds at different depths. Analysis from the angle of initial infiltration rate,stable infiltration rate,average infiltration rate,and infiltration angle shows that permeability declines steadily from the red earth layer down to the detritus layer. Therefore,this article proceeds from collapsing of mounds and water regime of the soil per se,with a view to elaborating water movement processes during the collapse of mounds or cliffs,exploring soil water characteristic curves of collapse mound profiles,including topsoil layer,red earth layer,streaked layer,and detritus layer,and their fitting processes with equations,and analyzing the mechanisms of how collapse mounds occur from the angle of soil moisture and pority. The study adopted field sampling and in-lab analysis together. Two typical profiles of collapse mounds in Southeast Hubei,Wuli and Yanglong were selected as subjects of the study. Soil water characteristic curves in various soil layers were plotted with the aid of a CR21 G high-speed thermostat centrifuge of the Hitachi Corp. and on the basis of the soil water characteristic curves,soil porocities of the various soil layers were analyzed. Meanwhile,equations were screened for fitting the various soil water characteristic curves of the profiles. Results showed as