{"created":"2023-06-19T10:29:42.508915+00:00","id":9686,"links":{},"metadata":{"_buckets":{"deposit":"f3aba41a-2a5a-490b-8883-b8ec16c380f7"},"_deposit":{"created_by":18,"id":"9686","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"9686"},"status":"published"},"_oai":{"id":"oai:muroran-it.repo.nii.ac.jp:00009686","sets":["41:227"]},"author_link":["55184"],"item_81_date_granted_17":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2018-03-23"}]},"item_81_degree_grantor_10":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"室蘭工業大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Muroran Institute of Technology"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"10103","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_81_degree_name_11":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_81_description_25":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_81_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Japan has a variety of volcanic ash soils that cause complicated geotechnical engineering problems in all the regions of the islands, i.e., in Hokkaido, Tohoku, Kanto, Chubu, Chugoku and Kyushu. The distribution of volcanic ground was widespread and each volcanoes has acted numerously over geological time. In Hokkaido, Japan, there are over forty Quaternary volcanoes, and pyroclastic materials cover over 40 % of its area. Sedimentary structure, components, distributional area and degrees of the weathering greatly differ with the depositional environment. Therefore, it is anticipated that the mechanical property of volcanic soil grounds will be diverged. Such volcanic soils have been also used as useful construction materials, especially man-made earth structures (embankments and cut slopes, etc.). However, a large number of earthquake- and rainfall-induced failures of artificial slopes such as cut slopes or embankments have been reported in Hokkaido, Japan. Examples include embankment slope failures due to the 2003 Tokachi-oki earthquake, cut slope failure on the Hokkaido Expressway (1999) due to rainfall and snow-thaw water in the spring. Therefore, volcanic soils have been classified as “problematic soils” in Japan engineering researches. Notwithstanding, the research on volcanic soils from the engineering standpoint is extremely superficial in comparison with cohesion and cohesionless soils. Internal erosion is one of the major causes of failures and accidents for soil structures such as embankments. Examples include slope failure of the Hokkaido heavy rainfalls in 2016 and collapses of dykes around Kinugawa River (2015) due to internal erosion such as piping phenomenon by heavy rainfall. Therefore, this paper aims at clarifying destabilization of volcanic coarse grained soils caused by internal erosion in which soil particles within soil structures are outflowed by seepage flow. In order to accomplish the purposes, field observation of a full-scale embankment was firstly carried out. Thereafter, a series of upward seepage test was conducted to grasp features of seepage behavior in volcanic soils and to investigate effects of differences in compaction conditions and the shapes of grain distribution curve on its behavior. Additionally, internal stability of volcanic soils under several geotechnical conditions was elucidated by empirical criteria such as Kenny & Lau’s, Kezdi’s and Li & Fannin’s criteria, etc. In this study, a volcanic coarse grained soil erupted from the Shikotsu caldera in Sapporo city, Hokkaido was used in the seepage tests. The sample was specified into pumice flow deposits (the notation is Spfl), and was referred to as Komaoka volcanic soils. In the experiments, the movement of soil particles in seepage flow tests was observed using an X-ray CT scanner in detail. The test results showed that destabilization of soil structures due to seepage flow is changed depending on an increase of amount of finer soil particles, and that internal erosion is induced by loss of fine particles with the changes in void ratio. As a result, a significant variation in hydraulic conductivity was generated. In the consideration of the results, it was shown that volcanic coarse grained soil including pumice particles with a low specific gravity is internally unstable. Finally, a new evaluation method on internal erosion was proposed for the stability of soil structures constructed by volcanic coarse grained soils by taking index properties and mechanical behavior of materials into account.","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"近年の豪雨災害，例えば2016年8月に発生した北海道豪雨での切土・盛土の斜面崩壊や2015年9月の鬼怒川の堤防決壊では，一部パイピングに起因すると考えられる浸食ならびに崩壊が報告されている。このような土構造物の内部浸食に起因する安定性評価は，現在もなお工学1級の問題として扱われている。実際，このような土構造物の構築の際には，現地の土質材料を利用する場合が多い。そのため，全面積の約40％を火山灰質土で覆われている北海道では，多くの土構造物において火山灰質粗粒土が利用されている。このような火山灰粗粒土は排水性が高く，良質な地盤材料として，今まで多くの土構造物に採用されてきた。しかしながら，その透水・通水特性について詳細に検討された事例は少ないのが現状である。一連の研究では，火山灰質粗粒土で構築された実大盛土斜面の降雨時・浸透時の崩壊挙動が調査されているが，崩壊後に解体した本盛土断面においてパイピングの痕跡が確認されており，パイピング現象が崩壊を助長した可能性があることを指摘している。このような内部浸食に関する既往の研究ではKenny and Lau, Kezdi, Li and Fanninの評価式などを代表するように，礫質土や砂質土の通常の土質材料に対する検討は行われているものの，粒子破砕性や非塑性かつ低土粒子密度を有する火山灰質土（特殊土）に対する検討および評価は行われていない。本研究では，北海道内に分布する代表的な火山灰質粗粒土（支笏を噴出源とする火山灰質土：Spfl）を用いて，パイピング，ボイリング現象に代表される内部浸食現象について工学的な検討を行っている。なお，この火山灰質粗粒土は，旧河川域を埋め立てて住宅盛土として使用した土質材料であり，1968年と2003年に発生した十勝沖地震で液状化した試料と同噴出源の試料である。本研究では，はじめに内部浸食に関する過去の研究事例を整理している。すなわち，従来より提案されている各評価式の火山灰質粗粒土への適用を調査し，地盤工学的な評価を行っている。次いで，火山灰盛土への浸透特性が力学的安定性に及ぼす影響をパイピング試験により明らかにしている。一連の実験では，X線CTスキャンの画像解析より浸透流にともなう土粒子個々の移動量を定量化し，パイピング現象のプロセスと土構造物の不安定化を導く要因を把握している。本研究の総括として，物性評価（示標特性）と力学的評価（浸透流による有効応力の評価）を取り入れた，火山灰質土の内部浸食に対する安定性評価手法を新たに提案している。","subitem_description_language":"ja","subitem_description_type":"Abstract"}]},"item_81_dissertation_number_13":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第417号"}]},"item_81_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15118/00009638","subitem_identifier_reg_type":"JaLC"}]},"item_81_subject_9":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"511","subitem_subject_scheme":"NDC"}]},"item_81_text_12":{"attribute_name":"学位の種別","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"課程博士"}]},"item_81_text_14":{"attribute_name":"報告番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"甲第417号"}]},"item_81_text_15":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"博甲第417号"}]},"item_81_text_16":{"attribute_name":"研究科・専攻","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"工学専攻"}]},"item_81_version_type_24":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorAffiliations":[{"affiliationNameIdentifiers":[],"affiliationNames":[{"affiliationName":""}]}],"creatorNames":[{"creatorName":"DAO, Minh Hieu","creatorNameLang":"en"}],"familyNames":[{}],"givenNames":[{}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2018-06-06"}],"displaytype":"detail","filename":"A417.pdf","filesize":[{"value":"18.5 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A417","objectType":"fulltext","url":"https://muroran-it.repo.nii.ac.jp/record/9686/files/A417.pdf"},"version_id":"9732fec6-e313-4d1f-97dd-8613645f335e"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2018-06-06"}],"displaytype":"detail","filename":"A417_summary.pdf","filesize":[{"value":"177.4 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A417_summary","objectType":"abstract","url":"https://muroran-it.repo.nii.ac.jp/record/9686/files/A417_summary.pdf"},"version_id":"cf384b52-3e39-4fff-be98-c1b0431ae1a1"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"STABILITY EVALUATION ON INTERNAL EROSION OF VOLCANIC COARSE GRAINED SOILS","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"STABILITY EVALUATION ON INTERNAL EROSION OF VOLCANIC COARSE GRAINED SOILS","subitem_title_language":"en"},{"subitem_title":"火山灰質粗粒土の内部浸食に関する安定性評価","subitem_title_language":"ja"}]},"item_type_id":"81","owner":"18","path":["227"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2018-06-06"},"publish_date":"2018-06-06","publish_status":"0","recid":"9686","relation_version_is_last":true,"title":["STABILITY EVALUATION ON INTERNAL EROSION OF VOLCANIC COARSE GRAINED SOILS"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2024-01-22T02:37:52.938326+00:00"}