为研究“旱季高温干燥、雨季降水集中且多暴雨”的干湿交替作用对冲沟形成过程的影响，选择干热河谷区典型发育的土层剖面（由上至下依次为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ层），采用干湿交替原位试验，选取土体抗剪强度、抗冲系数以及崩解性指标，分析不同土层抗侵蚀的特性及差异。研究结果表明：各土层抗剪强度差异明显，其中Ⅳ层和Ⅴ层抗剪强度较大；内摩擦角随干湿交替次数增多呈波动不定趋势而粘聚力则呈显著负相关关系；各土层抗冲性差异明显，其中Ⅲ层和Ⅵ层抗冲性较小；抗冲性随干湿交替次数增多而增大、剥蚀率则随干湿交替次数增多呈波动减小趋势；各土层平均崩解速度与干湿交替次数呈显著线性相关，Ⅲ层和Ⅵ层较大、Ⅳ层和Ⅴ层较小、Ⅰ层和Ⅱ层介于二者之间。各土层具有“软硬岩层相间”的发育特征，其抗蚀性在垂直方向大致呈现“减小—增大—减小”的趋势，该研究从土壤侵蚀的角度在一定程度上揭示了冲沟发展过程。

Gullies are well developed in Yuanmou dry-hot valley region of Southwest China,which result in intense soil erosion and severe land gradation. And local climate and soil properties are two of the main factors controlling gully erosion in this area. The frequent dry-wet alternations occurred in soil are the essential process of gully erosion. Six typical soil layers in the study area are chosen(from top to bottom are as follows: layersⅠ,Ⅱ,Ⅲ,Ⅳ,Ⅴ and Ⅵ) to analyze the characteristics and differences of soil erosion resistance by implementing in situ experiments of dry-wet alternation,in which soil shear strength,soil anti-scourability and soil disintegration indices are selected as the main measuring and evaluation indicators. Research results show that the values of soil shear strength of the six soil layers are apparently different,among which those of layer Ⅳ and layer Ⅴ are greater than those of other layers. With the increase of cycles of dry-wet alternation,the internal friction angle shows a fluctuating and irregular trend,while the cohesive force presents significantly negative correlation relationship in the same layer. The difference for the values of soil anti-scourability is significant among the six soil layers,and the values of layer Ⅲ and layer Ⅵ are relatively smaller than those of other layers. During the dry-wet alternation,the soil detachment rate shows a fluctuating and gradual decreasing trend and the soil antiscourability is increased with the times of dry-wet alternations in the same layer. The average soil disintegration rates of all layers appear distinct liner correlations with the times of dry-wet alternations, among which those of layer Ⅲ and layer Ⅵ are relatively greater and layer Ⅳ and layer Ⅴ are smaller, while layerⅠand layer Ⅱ are intermediate between the former groups. Furthermore,with the feature of soft rock formations alternate with hard ones,the soil layers show an trend of firstly decreasing,and then increasing and finally decreasing for its soil erosion resistance in the vertical direction. The above results contribute to revealing gully development processes from the perspective of soil erosion.