Abstract
A low-cost and simple monitoring method for early warning of landslides is proposed. To detect abnormal deformation of a slope, this method employs a tilt sensor in place of an extensometer on the slope surface. In order to examine the relevance of measuring rotation angle on a slope surface by tilt sensor, model tests were conducted, and rotation on the slope surface was observed together with slide displacement along the surface. The rotation data responded 30 min before failure in a model test, which could be useful as a signal for early warning. However, the behavior of rotation before failure varies from case to case, and thus, criteria to issue warning should be defined more carefully. For a model slope made of uniform loose sand, measurement of slide displacement along the slope surface is sensitive to failure at the toe, while the measurement of rotation on the slope surface is useful to detect the development of progressive failure upward along the slope. Wireless sensor units with microelectromechanical systems (MEMS) tilt sensor and volumetric water content sensor were also examined on a real slope in Kobe City, and a long-term monitoring was attempted. A simple but possible way to define the criteria of judgment to issue warning can be proposed based on combination of data obtained by the tilt sensors and volumetric water content sensors.
Reference
Ochiai H, Okada Y, Furuya G, Okura Y, Matsui T, Sammori T, Terajima T, Sassa K (2004) A fluidized landslide on a natural slope by artificial rainfall. Landslides 1(3):211–219
Orense RP, Towhata I, Farooq K (2003) Investigation of failure of sandy slopes caused by heavy rainfall. In: Proc. Int. Conf. on Fast Slope Movement—Prediction and Prevention for Risk Mitigation (FSM2003), Sorrento
Orense RP, Farooq K, Towhata I (2004) Deformation behavior of sandy slopes during rainwater infiltration. Soil Found 44(2):15–30
Towhata I, Uchimura T, Gallage CPK (2005) On early detection and warning against rainfall-induced landslide, Proc. of The First General Assembly and The Fourth Session of Board of Representatives of the International Consortium on Landslides (ICL). Springer, Washington, DC, pp 133–139
Uchimura T, Towhata I, Wang L, Seko I (2008) Simple and low-cost wireless monitoring units for slope failure. In: Proc. of the First World Landslide Forum, International Consortium on Landslides (ICL), Tokyo, pp 611–614
Acknowledgements
The authors appreciate corporation by Mr. K. Furumoto, Mr. H. Mori, and Ms. Y. Saito of the Public Works Research Institute, Tsukuba, Japan, who conducted the slope model tests. A part of this research is supported by Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science and Construction Technology Research and Development Subsidy Program of Ministry of Land, Infrastructure, Transport, and Tourism of Japan.
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Uchimura, T., Towhata, I., Lan Anh, T.T. et al. Simple monitoring method for precaution of landslides watching tilting and water contents on slopes surface. Landslides 7, 351–357 (2010). https://doi.org/10.1007/s10346-009-0178-z
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DOI: https://doi.org/10.1007/s10346-009-0178-z