红层缓倾角土质滑坡发育环境、分布规律及影响因素研究  

Study on Development Environment,Distribution Characteristics and Factors of Soil Landslides on Low-angled Rock Formation of Red Bed

作　　者：李江[1] 许强[1] 胡泽铭[1] 易靖松[1] 张群[1] 

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610051

出　　处：《科学技术与工程》2014年第12期88-93,共6页Science Technology and Engineering

基　　金：四川省科技支撑计划项目(2012SZ0066)资助

摘　　要：红层在我国分布广泛，红层地层孕育大量的滑坡，其发育环境和形成机理独特。对红层缓倾角土质滑发育环境、分布规律及影响因素的研究有助于揭示滑坡的成因机理。以四川省南江县50个土质滑坡为研究对象，通过详细的现场调查和室内统计，对土质滑坡的发育、分布规律及影响因素进行了深入研究。研究结果表明：①从空间分布上看，土质滑坡分布主要沿河流、沟谷呈线状、带状分布，在南部山区零星分布，规模以小型滑坡为主；绝大部分为浅表层土质滑坡，滑坡有成群爆发的特点；②滑坡前缘高程集中分布在700—900m范围内，坡度主要分布在20°～30°斜坡中，滑体厚度3～5m，物质组成为粉质黏土或粉质黏土夹碎石。阶梯型斜坡上滑坡较发育，凹型、凸型、直线型斜坡上弱发育；③大部分土质滑坡沿着基岩和堆积层的交界面滑动，滑床岩性通过物理力学性质、水理性质和岩性组合三方面对滑坡产生影响。冲沟型和陡坎型临空面斜坡上滑坡最为发育；④降雨是诱发区内土质滑坡最主要的外界因素；⑤构造作用通过地形地貌间接对滑坡产生影响；“512”汶川地震使部分斜坡土体变松，产生裂缝，在降雨作用下，变形进一步加大，最后失稳。Red beds widely distribute in China. Red bed is pregnant with a lot of landslides, and their development environment and formation mechanism are unique. The study on development environment, distribution characteristics and factors of soil landslides on low-angled rock formation of red bed contribute to reveal the formation mechanism of landslides. Using more than 50 soil landslides in Nanjiang County of Sichuan Province as the study objects, through the detailed field investigation and indoor statistics, the development environment, distribution characteristics and factors of soil landslides in Nanjiang County are intensively studied. The research results show that： ①Soil landslides mainly distribute along the river and gully with linear and zonal distribution, while some small landslides sporadically distribute in the southern mountain area. Most of the landslides occur on the shallow surface of the soil slope at the same time. ②The elevation of landslides, frontal edge intensively distributes between 700 m and 900 m, and degree of slope between 20° - 30°, thickness of landslide between 3 ~ 5 m. The landslides consist of silty clay and silty clay with breakstone. Most soil landslides occur on ladder type slope and concave, convex and linear slope are less. ③Most landslides slide along the interface between bed rock and accumulation hori- zon. The rock bed has an impact on landslides through physical and mechanical properties, hydraulic properties and rock combination. There are three kinds of free face in the area including deep erosion river, valley, ditch and scarp, landslides mostly develop in ditch and scarp free face area. ④Rainfall is the most important inducing factor. ⑤Geological formation has an effect on landslides indirectly by topography. The soil becomes limp and form cracks after Wenchuan earthquake. Deformation develop intensively in the act of rainfall. The slopes destroy in the end.

关 键 词：红层 土质滑坡 发育环境 分布规律 影响因素 

分 类 号：TU446[建筑科学—岩土工程]