季节冻土区冻融期黄土滑坡基本特征与机理

在我国北方大部分地区滑坡灾害的发生有两个高峰期,即雨季和冻融期,而目前对冻融期滑坡的研究尚处在起步阶段,导致对冻融期滑坡的防治效果远不及雨季滑坡。本文以甘肃黄土滑坡为研究对象,探索季节冻土区冻融期黄土滑坡的基本特征和形成机制。结果表明,季节性冻融作用是季节冻融期黄土滑坡滑坡发生的主要因素,其不但在斜坡表层产生强烈作用,而且可引起斜坡深处地下水富集、土体软化范围扩大和静、动水压力增大等冻结滞水效应,促使斜坡整体性大规模变形破坏,导致滑坡发生。

Characteristics and Mechanism of Landslides in Loess during Freezing and Thawing Periods in Seasonally Frozen Ground Regions

In most areas of northern China,there are two periods,that is,rainy and thawing periods,during which landslides and other geological disasters most frequently occur. At present,the researches on freezing-thawing landslides are still at the beginning,and the techniques of controlling this type of landslide are less studied than those of controlling rainfall landslides. The purpose of this study is to explore the fundamental characteristics and formation mechanism of the freezing-thawing landslides occurring in Gansu Province. The study shows that the seasonal freezing-thawing action is the main factor triggering this type of landslide,which not only causes failure strongly on the surface of slope,but also results in frozen perched water concentrated in the deep depth of slope. This action also contributes to the enlarging of the range of softening soil mass and the increasing of the dynamic and static water pressures,resulting in displacements of large soil mass of slope and finally the occurring of landslides.