A unified landslide classification system for loess slopes: A critical review

Abstract Over the last few decades, many landslide classification systems have been developed. Inconsistencies across these systems have inevitably led to ambiguity, confusion, and contradictions. Specifically, there has been no consensus on what types of slope movements and failures constitute landslides. As a result, landslide classification systems based on the same criteria do not always include the same types of slope failures. On the other hand, general landslide classification systems do not take into account the unique characteristics of slope failures in loess, which covers about 6.7% of the Earth's land surface. Most literature on loess is in Chinese and the nomenclature, both within the Chinese literature and between the Chinese and English literature, is often not readily comparable. Therefore, there is a need for a consistent and comprehensive system for classification of loess-slope failures to be developed to better manage these particular geohazards as the presence and interactions of humans with the environment in loess areas continue to increase. In this paper, a critical review of landslide classification systems was conducted to identify their limitations, as well as their relevant criteria for classifying loess-slope failures. Understanding the mechanisms underlying the failure of loess slopes is critical for creating a realistic and comprehensive classification system for slope failures. The classification systems of loess-slope failures unified in this paper are based on detailed analyses of the possible mechanisms underlying each class of failure. The primary classification criteria are types of movement and materials, with other descriptive criteria used to explain differences among different classes. For each class, one or two typical case histories are presented. A comprehensive collection of the literature reviewed in this study will facilitate future research on loess geohazards.