Loess Stratigraphy and Loess Landslides in the Chinese Loess Plateau

Abstract

Chinese Loess is a dust deposit brought by wind from North-West desert. In the past four decades, the age and the strata of the loess stratigraphy were well defined by dating and correlating with deep sea core isotopic curves. A standard loess stratigraphic profile and the correlation among the different areas are introduced, and typical river terrace with loess deposit is also illustrated. Loess has a loose texture and is sensitive to water, which makes it susceptible to failure during rain or engineering activities. Landslides on the Chinese Loess Plateau are the most common and widespread geological hazard, which results in human deaths and severe injuries. Moreover, it damages infrastructures such as road, tunnels, bridges, railway tracks and engulfs agricultural land every year. Based on the failure modes and motion characters, the loess slope failure can be classified into two main types, shallow slide, and deep-seated landslide. The shallow failure can be further divided into two types of small collapse and shallow flow slide; while the deep-seated failure can be divided into the four types of rapid long run-out slide, rapid flow slide, slow creep slide and quick slump slide. The mechanism of the landslide movement is controlled by the moisture state on the failure surface and the moving path. Based on the Sassa’s motion simulation model, the modified models for simulating the catastrophic long run-out loess landslides are proposed which consider the effects of curved moving path, frontal plowing, bed entrainment on the running distance and coverage area of the sliding materials.KeywordsLoessStratigraphyThe chinese loess plateauLandslideRun-outSimulationFailure mechanism