浅议晋西北地区土质边坡稳定问题

Discuss on Soil Slope Stability in the Northwest Region of Shanxi Province

晋西北地区主要为黄土堆积侵蚀地貌单元,梁峁发育、沟壑纵横,在宽阔的沟谷及其两岸,通常沉积较厚的上第三系(N2)和第四系(Q)松散堆积物。上第三系(N2)地层以干热气候条件下沉积的湖相、滨湖相红粘土为主,粘粒含量高、渗透性弱,在干湿环境交替作用下,具有弱膨胀性;第四系(Q)松散堆积物则以不同成因类型的新老(Q2、Q3)黄土为主,具有大孔隙、低强度、中高压缩性和湿陷性等特殊的工程性质。在该地区修筑的隧洞、公路及其它工业与民用建筑,大都存在不同规模和类型的边坡开挖与稳定问题。晋西北地区土质边坡,基本可分为Q3均质黄土边坡、混合土层边坡以及岩土边坡等类型,因其构成不同,不同类别的土质边坡,各有其特定的失稳机理。

The northwest region of Shanxi Province topographically belongs to loess erosion landform and is featured by loess hills intersected by irregular branching of tributaries.Main broad valleys and their banks are commonly occupied by thick Neogene and Quaternary loose deposit.The stratum of Neogene is composed of red clay which deposited as lake facies or lakeshore facies under dry and hot climate,and the red clay is characterized by rich clay,low permeability and weak swelling.The stratum of Quaternary is composed of loess which has special engineering properties due to its large porosity,low strength,medium to high compressibility and collapsibility.Stability of cut slope on such soils is one of the major engineering problems for all civil works projects in this area.The Soil Slope in this area can be divided into loess slope,composite soil slope and soil and rock slope,typical slope types of different soil compositions and their special failure mechanism are discussed in this paper.