Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 14 2nd EGU Alexander von Humboldt Conference "The role of Geophysics in Natural Disaster Prevention" 2008 10.5194/adgeo-14-173-2008 http://www.adv-geosci.net/14/173/2008/ http://www.adv-geosci.net/14/173/2008/adgeo-14-173-2008.html http://www.adv-geosci.net/14/173/2008/adgeo-14-173-2008.pdf 173 181 2008-01-02 Development of a ground displacement measurement method for failed slopes at the toes of landslides K. Higuchi higuti44@pwri.go.jp K. Fujisawa M. Tohei S. Okawa H. Shimomura T. Sakata Public Works Research Institute, Japan KOWA Co., Ltd., Japan PASCO Co., Ltd., Japan RADIC Co., Ltd., Japan Sediments produced by a slope failure of the toe of a landslide are assumed to prevent the spread of the failure. Thus, sediment removal is an emergency measure that must be done safely while the slope is observed. Observation must also be done safely without requiring workers to enter the failed slope to avoid secondary disasters. <br><br> Generally, a non-prism type totalstation is useful to measure ground displacement under such circumstances, because this type of totalstation can be used without placing targets on the slope. However, the lack of prisms results in problems related to the objectivity of measurement data, collimation error of the totalstation, measurement at night, and so on. <br><br> The authors have developed targets and a remote target placing method in order to resolve the above problems. As a result, we have established remote measurement technique for ground displacement on failed slopes at the toes of landslides. This paper describes the measurement technique that has been developed. Asano, H., Ishii, Y., and Tsunaki, R.: Study of Quantity of Landslide Movement Using a 3D Laser Scanner, Proc. of the Fortieth Conference of the Japan Landslide Society, 279&ndash;281, 2001. Sabo Technical Center: Sanashi River Slope Failure Countermeasure Study Committee: Field Survey Document, 2004. Yuzawa Sabo Office, Hokuriku Regional Development Bureau, Ministry of Land, Infrastructure and Transport: Feb. 10. Report on Emergency Restoration Countermeasure Work following the Sediment Failure Disaster on the Sanashi River in Yunotani-mura, 2004. Sabo Technical Center: Organizing the Quantity of Landslide Movement, 2001. Tsunaki, R., Fujisawa, K., Matayoshi, H., and Yanagihara, K.: 1998 Survey of Landslide Risk Locations, Internal Documents of the Landslide Division, Erosion Control Department, of the Public Works Research Institute, Ministry of Construction, 31&ndash;37, 1999. Japan Society of Civil Engineers, Committee on Rock Mechanics, Subcommittee on Slope Stability: Rock Slope Surveying and Countermeasures, 1999. Association of Precise Survey and Applied Technology: Progress of Surveying Technology, Fifteenth Anniversary Project Documents, 1995. Japan Association for Slope Disaster Management: Landslide Observation Handbook, 1997. Ruege, J. M.: Electric Distance Measurement, 3rd Edition, Springer-Verlag, 1990.