{"created":"2021-03-01T06:51:32.589846+00:00","id":32827,"links":{},"metadata":{"_buckets":{"deposit":"86ce92df-a14c-4c20-9624-e86ac63580d0"},"_deposit":{"id":"32827","owner":"1","owners":[],"pid":{"revision_id":0,"type":"depid","value":"32827"},"status":"published"},"_oai":{"id":"oai:repository.dl.itc.u-tokyo.ac.jp:00032827","sets":["80:4535:4747:4753","9:504:4538:4749:4754"]},"author_link":["127839","127838"],"item_4_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"Dynamic Fracture Analysis of Ground by Granular Assembly Simulation I"}]},"item_4_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1988-11-11","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"2","bibliographicPageEnd":"235","bibliographicPageStart":"201","bibliographicVolumeNumber":"63","bibliographic_titles":[{"bibliographic_title":"東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo"}]}]},"item_4_description_13":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_4_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"現在,地盤の動的解析の手法として,主に地盤を連続体と近似した解析法が用いられている.これらの手法は,破壊に至るまでの解析を主眼としており,破壊後の解析には多くの困難が伴い,土の非連続体に近い挙動を再現するにはきわめて不適当である.これまでのDEMでは,要素間は接触しない限り完全に不連続として取り扱われてきた.水分を含んだ砂や粘性土など一般的な土のマクロな挙動を,完全な非連続体で表すのは不適当である.そのため,DEMを地盤の解析手法に用いると多くの問題が生じる.例えば,初期条件としての力学的に安定したモデルの作製に長い時間がかかる.また,盛土やロックフィルダム,斜面といった不整形な形状のものは解析できない.土の粘性やロックフィル材料の噛みあいの効果を表せないからである.本研究では,DEMを基に,要素間をつないでいる物質の効果を法線方向と接線方向の2本の間隙バネでとりいれた方法を提案した.これにより,地盤や土質材料の持つ連続体としての性質と非連続体としての性質の両方を表せることを示した.また,DEMで使用されるパラメータの決定法やパッキングの方法などを提案した.さらに,今まで２次元領域で定式化されていたDEMを,ベクトル定式化により3次元領域に拡張し3次元解析を実施した.解析例として,2次元領域と3次元領域で崖の動的崩壊解析を行なった.崖モデルに亀裂が生じ,そこから要素がブロック状に崩れており,その後,支えを失った土塊がすべり線をつくって崩れている.間隙バネの分布図にはすべり線と亀裂,一体となった土塊がはっきりと表現された.間隙バネを設定することで,地山の破壊していない部分,破壊して崩れた部分や亀裂,すべり線を的確に表現することができる.この他各パラメータの影響も確認した.これらの解析結果より,間隙バネを取り入れたDEM解析法は,連続及び非連続な媒質の性質をともに扱えることがわかった.特に,従来は行えなかった地盤解析に効果的であることがわかった.また,3次元DEM解析が可能であることを示した.","subitem_description_type":"Abstract"},{"subitem_description":"The present study aims to simulate the dynamic fracture process of soil and soil structure by developing Cundall's Distinct Element Method (DEM) in which soil is represented as a system of numerous discrete particles and dynamic behavior of all those particles is calculated individually. This method is based on the idea that each particle satisfies the equation of motion and the interaction among them simply. This method could not consider, however, some important problems: continuity of the medium and wave propagation. Many problems which have not been solved by conventional continuous mechanics are treated with this method. The present paper improves this method so as to solve these problems. The new DEM consists of two structures: primary structure and secondary structure. The primary structure is the conventional DEM and is used to transmit the force through the contact points and to calculate particle movement. The secondary structure is used to present the continuity of the medium. For instance the first structure corresponds to rock or gravel and the second structure to internal clay. As a consequence, it can simulate wave propagation as well as dynamic fracture. For test, the presented method is applied to dynamic fracture of cliffs caused by an earthquake and succeeds in simulating the fracture process of the cliffs. At an early stage, small cracks appear and grow up to long ones. Finally the cracks form fracture lines, and blocks of soil begin to slide down. The second structure of the model detects the crack lines and discriminates broken area from stable area. These results suggest the applicability of the presented method to the study of the fracture problems of the soil and soil structures.","subitem_description_type":"Abstract"}]},"item_4_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"127839","nameIdentifierScheme":"WEKO"}],"names":[{"name":"Iwashita, Kazuyoshi"}]}]},"item_4_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15083/0000032827","subitem_identifier_reg_type":"JaLC"}]},"item_4_publisher_20":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"東京大学地震研究所"}]},"item_4_source_id_10":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN00162258","subitem_source_identifier_type":"NCID"}]},"item_4_source_id_8":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"00408972","subitem_source_identifier_type":"ISSN"}]},"item_4_subject_15":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"453","subitem_subject_scheme":"NDC"}]},"item_4_text_21":{"attribute_name":"出版者別名","attribute_value_mlt":[{"subitem_text_value":"Earthquake Research Institute, University of Tokyo"}]},"item_4_text_4":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"地震研究所"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"岩下, 和義"}],"nameIdentifiers":[{"nameIdentifier":"127838","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-06-26"}],"displaytype":"detail","filename":"ji0632008.pdf","filesize":[{"value":"2.5 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"ji0632008.pdf","url":"https://repository.dl.itc.u-tokyo.ac.jp/record/32827/files/ji0632008.pdf"},"version_id":"c285704f-ce63-43a9-b5b6-d57491ffcdf9"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"粒状体シミュレーションによる地盤の動的破壊解析 : その1","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"粒状体シミュレーションによる地盤の動的破壊解析 : その1","subitem_title_language":"ja"}]},"item_type_id":"4","owner":"1","path":["4753","4754"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-05-30"},"publish_date":"2008-05-30","publish_status":"0","recid":"32827","relation_version_is_last":true,"title":["粒状体シミュレーションによる地盤の動的破壊解析 : その1"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-12-19T04:08:46.477642+00:00"}