Underlying mechanisms of the geohazards of macro Loess discontinuities on the Chinese Loess Plateau

• Published in: Engineering geology Vol. 263; p. 105357
• Main Authors: Wang, Shaokai, Peng, Jianbing, Zhuang, Jianqi, Kang, Chenyun, Jia, Zhijie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.12.2019
• Subjects: China; landslides; loess; Loess discontinuities; Loess geohazards; Loess landslides; Loess Plateau; Mechanisms; seepage; terminology; China; Loess landslides; Mechanisms; Loess discontinuities; Loess geohazards; Loess Plateau
• ISSN: 0013-7952; 1872-6917
• DOI: 10.1016/j.enggeo.2019.105357

•An inventory of 13,798 loess discontinuities is established.•“Cutting degree” is defined to measure the scale of loess discontinuities, and five kinds of dicontinuity-scale are found.•The relationships between loess discontinuities and loess geohazards (or preferential seepage channels) are found.•The mechanisms for loess collapses and loess landslides of macro loess discontinuities are identified. Loess discontinuities are geological interfaces that are formed and continuously developed within loess during loessification. Typically, loess discontinuities include joints, cracks, fissures, and layer contact planes. In this study, 13,798 discontinuities on the Loess Plateau in China were examined to demonstrate the control mechanisms underlying loess geohazards. By comprehensively analyzing the collected data, the following could be concluded: (1) The scale of loess geohazards is proportional to the scale of the associated loess discontinuities; notably, a new terminology called “cutting degree” was defined to measure the scale of loess discontinuities. (2) Loess discontinuities provide sufficient conditions for both loess geohazards and preferential seepage channels. (3) The control mechanism for loess geohazards can be represented by a process --- “discontinuity, cave, gully, and sliding” (abbr. for DCGS). Furthermore, these conclusions provide fundamental information for the understanding of loess geohazards controlled by the combined characters of loess discontinuities and for forecasting of loess landslides on the Loess Plateau.