Precursors of instability in a natural slope due to rainfall: a full-scale experiment

• Published in: Landslides Vol. 15; no. 9; pp. 1745 - 1759
• Main Authors: Askarinejad, Amin, Akca, Devrim, Springman, Sarah M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2018; Springer Nature B.V
• Subjects: Agriculture; Civil Engineering; Compression; Compression zone; Deformation; Earth; Earth and Environmental Science; Earth pressure; Earth Sciences; External pressure; Failure; Geography; Hydrostatic pressure; Inclinometers; Instability; Landslides; Moisture content; Natural Hazards; Natural slope; Original Paper; Pore pressure; Pore water; Pore water pressure; Precursors; Pressure measurement; Rain; Rainfall; Rainmaking; Sensors; Slope indicators; Slope stability; Soil; Water content; Water pressure; Landslide monitoring; Slope deformation sensors; Geotechnical physical modelling; Unsaturated soils; Rainfall; Slope stability; Natural hazards; Slope movements
• ISSN: 1612-510X; 1612-5118
• DOI: 10.1007/s10346-018-0994-0

A full-scale landslide-triggering experiment was conducted on a natural sandy slope subjected to an artificial rainfall event, which resulted in mobilisation of 130 m 3 of soil mass. Novel slope deformation sensors (SDSs) were applied to monitor the subsurface pre-failure movements and the precursors of the artificially triggered landslide. These fully automated sensors are more flexible than the conventional inclinometers by several orders of magnitude and therefore are able to detect fine movements (< 1 mm) of the soil mass reliably. Data from high-frequency measurements of the external bending work, indicating the transmitted energy from the surrounding soil to these sensors, pore water pressure at various depths, horizontal soil pressure and advanced surface monitoring techniques, contributed to an integrated analysis of the processes that led to triggering of the landslide. Precursors of movements were detected before the failure using the horizontal earth pressure measurements, as well as surface and subsurface movement records. The measurements showed accelerating increases of the horizontal earth pressure in the compression zone of the unstable area and external bending work applied to the slope deformation sensors. These data are compared to the pore water pressure and volumetric water content changes leading to failure.