The Effect of Surface Layer Thickness in a Wide-Area Simulation in Different Models: Susceptibility Mapping of Rainfall-Induced Landslide
Akino Watanabe*1,, Akihiko Wakai*1, Takatsugu Ozaki*1, Thang Van Nguyen*1, Takashi Kimura*2, Go Sato*3, Kazunori Hayashi*4, and Nanaha Kitamura*1
1-5-1 Tenjincho, Kiryu, Gunma 376-8515, Japan
*2Ehime University, Ehime, Japan
*3Teikyo Heisei University, Tokyo, Japan
*4Okuyama Boring Co., Ltd., Miyagi, Japan
In recent years, sediment disaster has frequently been caused by heavy rainfall and has cost many human lives and great property losses. To estimate such risks, Wakai et al.  proposed a simplified prediction method to calculate the variation of groundwater levels in natural slopes both at the time of rainfall in wide areas and in real time. To calculate the variation of groundwater levels using this method, the slope conditions (such as material constant and initial conditions) must be determined in advance. This study takes the 2017 heavy rainfall in Northern Kyushu as an example to analyze surface layer thickness, one of the slope conditions that most significantly influences slope stability, over wide areas. The findings reveal that the prediction of slope failure distribution differs depending on how the surface layer thickness and sliding surface are determined.
-  A. Wakai, K. Hori, A. Watanabe, F. Cai, H. Fukazu, S. Goto, and T. Kimura, “A simple prediction model for shallow groundwater level rise in natural slopes based on finite element solutions,” J. of the Japan Landslide Society, Vol.56, Special Issue, pp. 227-239, 2019 (in Japanese).
-  R. Misumi, T. Oguchi, M. Maki, and K. Iwanami, “A real-time forecast of shallow landslides using a distributed rainfall-runoff model,” J. of Japan Society for Natural Disaster Science, Vol.23, No.3, pp. 415-432, 2004 (in Japanese).
-  T. Okimura, N. Torii, Y. Osaki, M. Nambu, and K. Haraguchi, “Construction of real-time type hazard system to predict landslides caused by heavy rainfalls,” J. of the Japan Society of Erosion Control Engineering, Vol.63, No.6, pp. 4-12, 2011 (in Japanese).
-  A. Kinoshita, T. Kanno, A. Okamoto, M. Hitokoto, M. Onodera, M. Sakuraba, and M. Sugiyama, “Construction of real-time hazard map system in Rokko mountain area,” J. of the Japan Society of Erosion Control Engineering, Vol.66, No.1, pp. 15-22, 2013 (in Japanese).
-  T. Ozaki, A. Wakai, A. Watanabe, F. Cai, G. Sato, and T. Kimura, “A simplified model for the infiltration of rainwater in natural slope consisting of fine sands,” J. of the Japan Landslide Society, Vol.58, No.2, pp. 57-64, 2021 (in Japanese).
-  F. Cai and K. Ugai, “Numerical analysis of rainfall effects on slope stability,” Int. J. of Geomechanics, Vol.4, No.2, pp. 69-78, 2004.
-  Japanese Association of Groundwater Hydrology, “Simulation of ground water flow and solute transport,” pp. 47-51, Gihodo Shuppan, 2010 (in Japanese).
-  W. Kinzelbach (Ed.), ”Groundwater modelling: An introduction with sample programs in BASIC,” pp. 29-35, Elsevier Science Ltd., 1986.
-  S. Yasuda, Y. Yamada, and T. Katada, “Soil mechanics,” pp. 153-154, Ohmsha, Ltd., 2014 (in Japanese).
-  Disaster Prevention Research Institute, Kyoto University, “Report of the 2017 Northern Kyushu Heavy Rain Disaster Research Mission,” p. 49, 2018 (in Japanese).
-  Geospatial Information Authority of Japan, https://www.gsi.go.jp/BOUSAI/H29hukuoka_ooita-heavyrain.html [accessed July 14, 2019]
-  Geological Survey of Japan, “Seamless Digital Geological Map of Japan (1:200,000),” https://gbank.gsj.jp/seamless/v2.html [accessed November 22, 2020]
-  Environmental Systems Research Institute (ESRI), “Raster Surface toolset concepts, How Slope works,” https://desktop.arcgis.com/ja/arcmap/10.3/tools/3d-analyst-toolbox/how-slope-works.htm [accessed November 22, 2020]
-  I. Kamiya, T. Kuroki, and K. Tanaka, “Interpretation of geomorphology and geology using slope gradation map,” Geoinformatics, Vol.11, No.1, pp. 11-24, 2000 (in Japanese).
-  Japan Road Association, “Manual for Asphalt Pavement,” p. 114, 1990 (in Japanese).
-  S. Chiba et al., “Survey case report on a slope that collapsed due to heavy rain in northern Kyushu in 2017 Part 1 – Comparison of characteristics of surface collapsed areas in three geological zones –,” JSECE Publication, No.83, pp. 153-154, 2018 (in Japanese).
-  Y. Yoshimi and Architectural Structure Editorial Committee, “Soil mechanics,” p. 97, Shokokusha, 1967 (in Japanese).
-  T. Okimura, “A method for estimating potential failure depth used for a probable failure predicting model,” J. of the Japan Society of Erosion Control Engineering, Vol.42, No.1, pp. 14-21, 1989 (in Japanese).
-  Y. Sakai, A. Kinoshita, K. Ogawa, and M. Nakata, “Estimation of surface soil layers depth by Terrain Analysis from LiDAR data,” J. of the Japan Society of Erosion Control Engineering, Vol.64, No.6, pp. 38-42, 2012 (in Japanese).
-  The Japan Society of Erosion Control Engineering, “Committee report on basic matters related to landslide,” JSECE Publication No.65, p. 12, 2012 (in Japanese).
-  Kyushu Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism, “Restoration Committee Report on the right bank of the Chikugo River,” http://www.qsr.mlit.go.jp/bousai_joho/H29hokubugouu/taisaku.html (in Japanese) [accessed March 18, 2021]
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