长江上游侵蚀、滑坡和泥石流典型区土体特性及微形态学研究

A Study on Soil Features and Micromorphology in Typical Erosion,Landslide and Debris Flow-Occurred Regions in Upper Reaches of Yangtze River

长江上游地区的侵蚀、滑坡和泥石流发生普遍而严重。选择典型区对侵蚀、滑坡和泥石流土体的微形态及与之紧密相关的土性进行比较研究,有重要意义。在贡嘎山东坡、川中丘陵盐亭、三峡库区云阳、云南东川蒋家沟分别采集代表性侵蚀、滑坡和泥石流土体剖面进行了研究。主要取得下述研究结果：(1)不同侵蚀强度的研究区土体特性有所不同,但共同特征是发育浅、颗粒粗、易分散等,有利于侵蚀形成；也相应形成一些侵蚀土体的微形态特征,如粗骨颗粒聚积状微形态、细土物质微区淋蚀现象、埋藏土层微形态特征等。(2)在滑坡土体,发现一些有利于滑坡形成的土体特性和微形态特征,如骨骼颗粒细化和蚀圆化、吸水性强的指纹状微结构等。在滑塌面上形成特殊的土体微形态,如拉张微裂隙、强光性定向粘粒集合体、玻璃质形成物、铁锰分离物等。(3)泥石流土体土性特殊,并形成了一些特殊的土体微形态特征,如湖泥状基质、骨骼颗粒泥质包裹体、错断微裂隙等。结果表明：在不同的环境条件下,三类土体的土性和土体微形态也有异同。对侵蚀、滑坡和泥石流的形成机制、活动性等都有一定的诊断意义。

Erosion, landslide and debris flow occurred widespread and severely in upper reaches of Yangtze River. It is very significant to study the soil features and micromorphology of erosion, landslide and debris flow in typical regions. In this paper, the soil profiles of typical erosion, landslide and debris flow from eastern slope of Mt. Gongga, Yanting in hilly region of central Sichuan, Yunyang in Three Gorges as well as Jiangjia Ravine of Dongchuan in Yunnan Province were conducted, the main results are as follow： （ 1 ） The soil features are different in the regions with different erosion intensity, however, such features as weak development, coarse particles, easy dispersion are common, which are in favor of the formation of erosion, consequently, some micromorphology of erosive soil formed, for example, micromorphology of coarse skeleton accumulation, micro-spotleaching of fine soil, micromorphology of buried soil horizon etc. （2） The micromorphology and features of favorable landslide formation in landslide soil were observed, e. g. , fine andround-eroded skeletons, fingerprint microstrueture of favorable attenuating water and so on. Some peculiar micromorphology also was found in landslide bed such as tensile micro-crack, optical beamed clay aggregates, Fe-Mn isolates and glassy materials. （3） The soil of debris flow are very special in features and has peculiar micromorphology, for example, lacustrinemuddy-like matrix, rock fragment-coated muddy inclusions, dislocation microstrueture and so on. The results revealed that the features.and micromorphology of three type of soil are different because of their different environmental condition, which has taxonomic implication for the formation of erosion, landslide and debris flow.