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朝比奈 大輔*; 青柳 和平; Kim, K.*; Birkholzer, J.*; Birkholzer, J. T.*; Bolander, J. E.*
Computers and Geotechnics, 81, p.195 - 206, 2017/01
被引用回数：33 パーセンタイル：82.31(Computer Science, Interdisciplinary Applications)This study involves the development of the auxiliary stress approach for producing elastically-homogeneous lattice models of damage in geomaterials. The lattice models are based on random, three-dimensional assemblages of rigid-body-spring elements. Unlike conventional lattice or particle models, the elastic constants of a material (e.g., Young's modulus and Poisson's ratio) are represented properly in both global and local senses, without any need for calibration. The proposed approach is demonstrated and validated through analyses of homogeneous and heterogeneous systems under uni- and tri-axial loading conditions. Comparisons are made with analytical solutions and finite element results. Thereafter, the model is used to simulate a series of standard laboratory tests: (a) split-cylinder tests, and (b) uniaxial compressive tests of sedimentary rocks at the Horonobe Underground Research Laboratory in Hokkaido, Japan. Model inputs are based on physical quantities measured in the experiments. The simulation results agree well with the experimental results in terms of pre-peak stress-strain/displacement responses, strength measurements, and failure patterns.
Kim, M.; Malins, A.; 町田 昌彦; 斎藤 公明; 長谷川 幸弘*; 柳 秀明*
no journal, ,
A priority after nuclear accidents is reducing radiation exposures for people living in long-term contaminated areas. An important contributor to radiation doses is external exposure to gamma rays from radioactive 
Cs and 
Cs. External exposure levels depend on the amount and distribution of Cs and Cs in the environment, the attenuation of gamma rays by matter, and the characteristic locations where people tend to spend time during their daily lives. Understanding and minimizing radiation exposures therefore requires good models connecting the distribution of Cs and Cs in the environment with gamma radiation dose rates in the air. The 3D Air Dose Rate Evaluation System (3D-ADRES) was developed in response to this issue. The main application of 3D-ADRES is for creating 3D models of locations in Fukushima Prefecture which are suitable Particle and Heavy Ion Transport code System (PHITS) radiation transport simulations. 3D-ADRES takes remote sensing data, such as satellite and aerial orthophotos, and digital elevation and surface models (DEM & DSM), and presents users with an interface for creating multi-faceted models of target sites. DEM data are used for creating a topographic model of the land surface. DSM data and the orthophotos are used for adding buildings and trees to the model, and for classifying different types of land surface, e.g. paved, soil and forest areas. Users are then able to set flexibly the amount of Cs and Cs within different areas and objects in the model.
