{"created":"2022-01-27T07:27:39.335181+00:00","id":2003220,"links":{},"metadata":{"_buckets":{"deposit":"5b82039a-7e76-4985-b774-d8bcdc1aaca3"},"_deposit":{"id":"2003220","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"2003220"},"status":"published"},"_oai":{"id":"oai:u-ryukyu.repo.nii.ac.jp:02003220","sets":["1642837622505:1642837905044:1642837910985","1642838403551:1642838407312"]},"author_link":[],"item_1617186331708":{"attribute_name":"Title","attribute_value_mlt":[{"subitem_1551255647225":"乾湿繰返しによる島尻層泥岩の強度低下(農業工学科)","subitem_1551255648112":"ja"},{"subitem_1551255647225":"On the strength decrease of Shimajiri Mudstone due to alternate drying and wetting as physical weathering (Department of Agricultural Engineering)","subitem_1551255648112":"en"}]},"item_1617186419668":{"attribute_name":"Creator","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"新城, 俊也","creatorNameLang":"ja"}]},{"creatorNames":[{"creatorName":"小宮, 康明","creatorNameLang":"ja"}]},{"creatorNames":[{"creatorName":"Shinjo, Toshiya","creatorNameLang":"en"}]},{"creatorNames":[{"creatorName":"Komiya, Yasuaki","creatorNameLang":"en"}]}]},"item_1617186476635":{"attribute_name":"Access Rights","attribute_value_mlt":[{"subitem_1522299639480":"open access","subitem_1600958577026":"http://purl.org/coar/access_right/c_abf2"}]},"item_1617186626617":{"attribute_name":"Description","attribute_value_mlt":[{"subitem_description":"本研究では泥岩の強度低下の要因として吸水膨張と乾湿風化を取上げた。吸水膨張による強度低下の経時変化, 乾湿作用を繰返し作用させたときの強度低下, せん断特性の変化を室内実験で定性的に把握し, その結果と風化土の結果と比較して, 実際の斜面保護・安定性との関連性ならびに安定解析について2・3の考察を試みた。その結果をまとめると次のようになる。1)吸水膨張による強度低下は時間の対数とともに直線的に進行し, ほぼ1年後に初期強度の67%まで減少する。2)乾湿を1サイクルに限定すると, 乾燥含水比が低いほど液性限界は減少する。同様にスレーキングも激しくなり, それに対応して強度減少も著しく, 自然含水比より2∿3%の含水比減少で初期強度の65%に, 気乾4%では20%にも減少する。3)泥岩の結合力破壊度合は乾燥含水比が低いほど著しく, 強度定数の粘着力成分c'の減少をもたらすが, 乾湿1サイクルだけでは十分軟弱化しない。4)スレーキング特性は乾燥法と拘束条件によって異なるが, 特に拘束条件の影響が著しい。5)乾湿繰返しによって生じた細レキ状の塊からなる供試体のCU-試験によると, 低側圧では粒状体として挙動し, 中位の側圧では塊そのもののせん断を生じ, 破壊包絡線は曲線を示す。6)乾湿15サイクルの強度定数c'=0.05kg/cm^2,φ'=39.5°で, 練返して正規圧密した試料のc'=0 φ'=23°より大きい。7)風化表層土の強度定数は乾湿15サイクルと練返して正規圧密した試料の間にある。8)乾湿15サイクル供試体でもピーク強度後さらに変位を与えると, その強度定数は練返して正規圧密した試料の強度まで減少する。9)したがって, 乾湿作用は強度低下を著しく促進させる主要因となり, 原位置で引き続き長期にわたって化学的風化や進行性破壊の影響を受けると最終的には練返して正規圧密した試料の状態まで軟弱化すると推察される。10)得られた実験結果にもとづいて島尻層泥岩斜面の保護・安定性について検討した。特にこれまで発生したいくつかの地すべり, 斜面崩壊について有効応力による安定解析を検討した結果, 用いる強度定数として, 過去にすべった斜面に対し残留強度が, また, 現在すべり発生の兆候ある斜面に対してc'=0,φ'=23°がある程度妥当な値である。","subitem_description_type":"Other"},{"subitem_description":"The objection of this study is to clarify the strength decrease on mudstone due to alternate drying and wetting. Mudstone which deposited in Miocene Epoch of Tertiary Period is obtained from Yonabaru formation belonging to Shimajiri Stratum. In laboratory fall-cone tests and triaxial compression tests are carried out to investigate strength softening under immersion and variation of shear strength properties with slaking cycles. The test results are compared with those of weathered in-situ soils. The conclusions are as follows. The agent of alternate drying and wetting is an important factor that is related to the strength decrease of mudstone and the strength of mudstone subjected to alternate drying and wetting decreases until that of the remolded normally consolidated sample due to chemical weathering and progressive failure and so forth, therfore the shear strength parameter of the remolded normally consolidated sample is available for the analysis of first-time slide to slopes constituted of mudstone.","subitem_description_type":"Other"},{"subitem_description":"紀要論文","subitem_description_type":"Other"}]},"item_1617186643794":{"attribute_name":"Publisher","attribute_value_mlt":[{"subitem_1522300295150":"ja","subitem_1522300316516":"琉球大学農学部"}]},"item_1617186702042":{"attribute_name":"Language","attribute_value_mlt":[{"subitem_1551255818386":"jpn"}]},"item_1617186783814":{"attribute_name":"Identifier","attribute_value_mlt":[{"subitem_identifier_type":"HDL","subitem_identifier_uri":"http://hdl.handle.net/20.500.12000/4206"}]},"item_1617186920753":{"attribute_name":"Source Identifier","attribute_value_mlt":[{"subitem_1522646500366":"ISSN","subitem_1522646572813":"0370-4246"},{"subitem_1522646500366":"NCID","subitem_1522646572813":"AN00250548"}]},"item_1617186941041":{"attribute_name":"Source Title","attribute_value_mlt":[{"subitem_1522650068558":"ja","subitem_1522650091861":"琉球大学農学部学術報告"},{"subitem_1522650068558":"en","subitem_1522650091861":"The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus"}]},"item_1617187056579":{"attribute_name":"Bibliographic Information","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1978-12-01","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"25","bibliographicPageEnd":"323","bibliographicPageStart":"307"}]},"item_1617258105262":{"attribute_name":"Resource Type","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_1617265215918":{"attribute_name":"Version Type","attribute_value_mlt":[{"subitem_1522305645492":"VoR","subitem_1600292170262":"http://purl.org/coar/version/c_970fb48d4fbd8a85"}]},"item_1617605131499":{"attribute_name":"File","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_access","filename":"KJ00000161960.pdf","mimetype":"application/pdf","url":{"objectType":"fulltext","url":"https://u-ryukyu.repo.nii.ac.jp/record/2003220/files/KJ00000161960.pdf"},"version_id":"bf870a03-084b-4cb4-8136-84a4007879b5"}]},"item_title":"乾湿繰返しによる島尻層泥岩の強度低下(農業工学科)","item_type_id":"15","owner":"1","path":["1642837910985","1642838407312"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-02-14"},"publish_date":"2008-02-14","publish_status":"0","recid":"2003220","relation_version_is_last":true,"title":["乾湿繰返しによる島尻層泥岩の強度低下(農業工学科)"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-10-31T01:17:53.525364+00:00"}