NHESS Natural Hazards and Earth System Sciences NHESS Nat. Hazards Earth Syst. Sci. 1684-9981 Copernicus Publications Göttingen, Germany 10.5194/nhess-14-2627-2014 Rockslides on limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China Feng Z. 1 Li B. 1 Yin Y. P. 2 He K. 3 Key Laboratory of Neotectonic Movement and Geohazard of MLR at Institute of Geomechanics, Chinese Academy of Geological Science, Beijing, 100081, China China Institute of Geo-Environment Monitoring, Beijing, 100081, China Chang'an University, Xi'an, 710054, China 29 09 2014 14 9 2627 2635 Copyright: © 2014 Z. Feng et al. 2014 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://nhess.copernicus.org/articles/14/2627/2014/nhess-14-2627-2014.html The full text article is available as a PDF file from https://nhess.copernicus.org/articles/14/2627/2014/nhess-14-2627-2014.pdf

Calcareous mountainous areas are highly prone to geohazards, and rockslides play an important role in cliff retreat. This study presents three examples of failures of limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China. Field observations and numerical modeling of Yudong Escarpment, Zengzi Cliff, and Wangxia Cliff showed that pre-existing vertical joints passing through thick limestone and the alternation of competent and incompetent layers are the most significant features for rockslides. A "hard-on-soft" cliff made of hard rocks superimposed on soft rocks is prone to rock slump, characterized by shearing through the underlying weak strata along a curved surface and backward tilting. When a slope contains weak interlayers rather than a soft basal, a rock collapse could occur from the compression fracture and tensile split of the rock mass near the interfaces. A rockslide might shear through a hard rock mass if no discontinuities are exposed in the cliff slope, and sliding may occur along a moderately inclined rupture plane. The "toe breakout" mechanism mainly depends on the strength characteristics of the rock mass.

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