Effective and economical slope disaster prevention strategy for reduction of isolated areas and period after strong earthquake

研究成果の概要 (和文) : （１）1995年兵庫県南部地震，2004年新潟県中越地震，2014年長野県神城断層地震，2016年熊本地震における斜面崩壊被害と道路防災点検データ等をもとに，地震時の斜面崩壊確率算定式を提案した．また，斜面崩壊確率と崩土流動域との関係を示した．さらに，崩壊確率算定式を和歌山県南部と長野県北部地域への適用を試み，孤立地域推定に対する有用性を示した．（２）岩手・宮城内陸地震で国内最大級の地すべりを起こした荒砥沢地すべり地の現地調査ならびに土質資料の採取，室内試験等を行い，その荒砥沢地すべり地の3次元SPH解析を行った．SPH解析の減衰や時間積分法を改良することで解の安定性，精度を改善した．
研究成果の概要 (英文) : (1)We proposed some equations of probability on slope collapse during strong earthquake based on the slope damages during the 1995 Kobe, the 2004 Chuetsu, the 2014 Kamishiro fault and the 2016 Kumamoto earthquakes, as well as the road disaster prevention check data. We indicated the validation for the isolated areas assessment in the southern Wakayama and the northern Nagano by using the results of statistical analysis for the relationship between the slope damage probability and the road damage.(2)We conducted twice field surveys at Aratozawa where one of the largest landslide in Japan occurred during the 2008 Iwate-Miyagi inland earthquake, and laboratory tests of the soil and the rock samples. Based on the test results, we performed three dimensional Smoothed Particle Hydrodynamics analyses for the landslide. We also improved the methodologies of time integration and damping calculation for analytical stability and accuracy.