論文 - 末次 大輔
-
中詰め材と金網の種類の違いが蛇籠の圧縮特性に与える影響 査読あり
中澤博志，末次大輔，原忠，栗原裕之，西剛整
材料 73 ( 1 ) 46 - 51 2024年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zairyo/Journal of the Society of Materials Science, Japan
The advantage of gabion structures is that they are simple, cost-effective, and quick to construct, and they are used in a wide variety of applications in Japan and abroad. However, despite the fact that wire mesh comprising the gabion has been used for a long time, there are few studies on its basic mechanical properties. Therefore, the design and construction of gabion structures are mostly based on experience due to the lack of established design methods. In this study, large triaxial compression tests on the stones for filling into gabion boxes and a series of compression tests on miniature gabions were carried out in order to understand the basic mechanical properties of the structures. From the tests, the compressive properties of the miniature gabions were found to be varied depending on the difference of geometry of the stone and the combination of the shape and direction of the wire mesh. These results suggest that an understanding on deformation mechanism of gabion structures is necessary for their reasonable design and construction.
DOI： 10.2472/jsms.73.46
-
EFFECT OF DIATOMACEOUS EARTH ON DESICCATION CRACKING OF EXPANSIVE SOILS 査読あり
Tadesse A.B., Fukubayshi Y., Koyama A., Suetsugu D.
International Journal of GEOMATE 24 ( 105 ) 66 - 76 2023年5月
掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of GEOMATE
Expansive soils shrink and swell, causing considerable density differences as the moisture content varies and cracks develop as the soil dries. This cracking condition has a detrimental effect on the stability of infrastructure built on expansive soil, such as road embankments. This paper investigates the influence of diatomaceous earth (at 5%, 10%, 15%, and 20% DE percent by mass) on the desiccation cracking of expansive soils. The report demonstrates an image analysis technique to describe soil surface cracking quantitatively. The geometric features of cracks, such as surface crack area and crack connectivity, were estimated and examined. The study considers soil crack area ratio and cracking index to investigate the effect of diatomaceous earth on expansive soil surface cracking. The crack area ratio and cracking index analysis results show that the expansive soil surface cracking is uneven and significant. The soil matrix containing 10% and 20% diatomaceous earth has reduced surface cracking and a homogenous radial cracking pattern. The image analysis approach, an essential method to quantitatively quantify soil desiccation cracking, revealed that diatomaceous earth substantially affects surface crack reduction.
-
日南層群分布域の道路斜面の動態観測と地下水位推定による地すべり挙動の検討 査読あり
伊集院 弘尚, 福林 良典, 神山 惇, 末次 大輔
地盤工学会災害調査論文報告集 1 ( 1 ) 121 - 137 2023年4月
担当区分：最終著者 記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 地盤工学会
イモ洗いのニホンザルが生息する宮崎県串間市の幸島から，南へ2.0kmほど国道448号を南下した箇所で，令和2年7月豪雨により路側構造物や道路に変状をきたす道路災害が発生した。当該箇所は，平成22年（2010年）から現在に至るまで，数回にわたり被災・復旧を繰り返している箇所であり国道448号の道路管理上の要ともいえる場所である。令和2年7月豪雨においては，擁壁の増し打ちアンカーの抜け出し，擁壁の傾倒・沈下，道路のクラック等の変状が確認され，全面通行止めによる通行規制が数か月間に渡り実施された。人的被害の発生は免れたものの，地域経済や観光業，緊急輸送道路としての機能に少なからず影響を与え，地域住民の生活に大きな制限を強いたことは言うまでもない。本事例報告においては，過去に発生した被災状況及び令和2年7月豪雨で発生した被災状況を紹介しながら，地盤工学的観点から，同じ箇所で繰り返し発生する道路災害防止に関しての1つの考えを述べるものである。
-
宮崎県西米良村における国道219号線での道路盛土の崩壊と復旧工 査読あり
神山 惇, 福林 良典, 伊集院 弘尚, 末次 大輔
地盤工学会災害調査論文報告集 1 ( 1 ) 115 - 120 2023年4月
担当区分：最終著者 記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 地盤工学会
令和2年7月豪雨により，宮崎県西米良村にある国道219号の道路盛土が崩壊した。当該現場は令和元年台風17号においても同様な被害が生じている。本稿では，令和2年7月豪雨における当該現場での被災状況調査結果について報告するとともに，過去の豪雨による被害事例について述べる。そして，今回の被害を受け設計，施工されている復旧工の様子を示す。
-
Fukubayashi Y., Koyama A., Suetsugu D.
E3S Web of Conferences 368 2023年2月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：E3S Web of Conferences
In African countries, in order to improve the trafficability of earth and gravel road, locally available material-based and labour-based approach are regarded as one of the most practical measures. As one of the approaches, a base course reinforcement method using Do-nou, which is the Japanese term for soil bag, had been developed. In this study, the bearing capacity of base course built with Do-nou has been examined through the Dynamic Cone Penetration tests (DCP). The series of full-size driving tests have been conducted with varying base structures and compaction methods. The results of the DCP tests show that, only in the case of Do-nou reinforcement base with manual compaction, the strength distribution balance at the part of base course and subgrade within 800 mm in depth from surface was shifted from average to well after being subjected to traffic load. In the other two cases, the balance remained average. It presents that by reinforcing soil material with Do-nou bags, the base course compacted manually keeps the sufficient bearing capacity and well-balanced strength profile in depth comparing with those conventionally designed and constructed with equipment.
-
Koyama A., Akira Y., Mitabe H., Fukubayashi Y., Suetsugu D.
Case Studies in Construction Materials 18 2022年12月
担当区分：責任著者 記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Case Studies in Construction Materials
The method of filling the lower space of a bridge with rigid polyurethane foam (RPU foam) to reduce the traffic load along with seismic reinforcement has rarely been applied to extend the life of bridges in Japan. This study evaluates the reinforcement effect and change in the vibration characteristics of a bridge converted into a lightweight embankment by RPU foam filling. A truck was driven on the bridge before and after the RPU foam filling. The vibration and strain of the slab were found to have reduced at the span center. When a traffic load was applied, the predominant frequency inside the RPU foam was ∼5 Hz, and long-period vibrations relative to the slab were confirmed.
-
粘性土中に打設される木杭の鉛直支持力に及ぼす杭形状の影響 査読あり
末次 大輔, 那須 龍斗, 神山 惇, 福林 良典
土木学会論文集E2（材料・コンクリート構造） 77 ( 5 ) I_77 - I_83 2022年3月
担当区分：筆頭著者, 責任著者 記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
Performance of labor-intensive base course for gravel roads with application of Do-nou 査読あり
Fukubayashi Y., Koyama A., Suetsugu D.
Transportation Engineering 7 2022年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Transportation Engineering
Community participation in road construction and repair is necessary in improving rural roads in developing countries, more than 50% of which are in poor condition caused by less involvement by the government due to budget constraints. To promote community participation, constructing base course with do-nou, the Japanese term for soil bag, which does not require the use of compaction equipment, has been proposed as a practical method. To extend the application of this method, the method must be adopted by stakeholders and its performance must be clearly understood. In this study, to compare the performance of the base course constructed with do-nou with that of the conventional structures constructed with equipment based on the existing manual for low-volume roads, a series of full-size model driving tests were conducted. Silty sand with gravel was selected as the base course material that is locally available and can be practically used in rural areas of developing countries. The deformation of the base course reinforced with do-nou under traffic loading was 14.0%. By contrast, the deformation for the base course compacted with equipment was 4.9% and that for the base course compacted manually without reinforcement with do-nou was 20.9%. The results of a dynamic cone penetration survey revealed that encapsulating the base course material in do-nou bags efficiently converted the traffic load into compaction energy and thus developed a balanced strength profile. Base course reinforced with do-nou behaved as an aggregate of distinct elements of do-nou and transferred a smaller load to the subgrade when subjected to traffic loading compared with nonreinforced base courses compacted manually and with equipment. The base course with do-nou and manual compaction did not perform as well as the base course compacted with equipment; however, it demonstrated intermediate performance with surface settlement of less than the maximum allowable level of 50.8 mm. The thickness of the base course reinforced with do-nou can be determined according to the existing design manual. The degree of compaction of base course constructed labor-intensively is initially insufficient. Therefore, once the road is opened to traffic, traffic should pass over the entire width of the road in dry conditions to accelerate compaction and improve road performance.
-
Koyama A., Suetsugu D., Fukubayashi Y., Mitabe H.
Construction and Building Materials 321 2022年2月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Construction and Building Materials
Frequent major earthquakes in Japan necessitate earthquake-resistant infrastructure. The dynamic deformation characteristics of rigid polyurethane foam, used as a lightweight embankment material, is examined in this study. The effect of the initial static stress on the shear modulus of single-layer samples was small, while the shear modulus of two-layer samples increased with increasing initial static stress. The damping ratio of single-layer samples converged to 4–5%, but decreased with increasing initial static stress up to 30 kPa in two-layer samples before increasing above 40 kPa. Results from cyclic uniaxial and triaxial tests were compared. The dynamic properties depended on restriction conditions and the deformation direction.
-
Nakazawa H., Ishizawa T., Danjo T., Onoue Y., Suetsugu D., Hara T.
Lecture Notes in Civil Engineering 209 LNCE 56 - 67 2022年
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Lecture Notes in Civil Engineering
In this study, based on the damage survey in Nepal, shake table tests and rainfall experiments using a typical gabion retaining wall model were conducted to investigate the influence on earthquake and rainfall basically. In a series of experiments, two same models with retaining wall with slope ground same as typical gabion retaining wall in Nepal were constructed in rigid soil container. Then, the model experiments containing shake table test after preceding rainfall and rainfall after preceding shake table test were simultaneously performed in order to confirm difference of the damage aspects caused by pattern of earthquake and rainfall. As main results, it was confirmed that the deformation tendency of the gabion retaining wall was different by the order of rainfall and earthquake. Especially, the deformation of the retaining wall in Case of preceding shake table test was minor compared to preceding rainfall. Regardless of the order by rainfall and earthquake, the gabion retaining wall showed the same tendency on deformation mode.
-
Deformation Resistance of the Gabion Retaining Wall Under Horizontal Loading 査読あり
Suetsugu D., Nakazawa H., Hara T., Fukubayashi Y., Koyama A.
Lecture Notes in Civil Engineering 209 LNCE 999 - 1007 2022年
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Lecture Notes in Civil Engineering
This research investigated the effects of the connecting gabions, the packing density and the particle shape of the filling gravel, and the vertical pressure on the horizontal deformation resistance of the gabion retaining wall. The dimensions of the model gabion used in this experiment were 20 cm × 20 cm × 20 cm. The model gabion retaining wall was prepared by stacking three of them vertically. The horizontal loading tests were performed with a plane strain, in which a gabion in the middle of the retaining wall was pushed horizontally while applying constant vertical load. The obtained main findings are as follows. 1) The connecting gabions have the effect of increasing the deformation resistance due to the generation of tension in the gabion net due to the deformation of itself. 2) The particle shape of the filling gravel affects the deformation resistance of the gabion retaining wall. That is, the rigidity of the gabion retaining wall using the round gravel at a small deformation level was stiffer than in the case using the angular gravel. 3) The vertical stress acting on the gabion retaining wall has little influence on its deformation resistance.
-
原 弘行, 藤江 佑大, 末次 大輔
土木学会論文集B3（海洋開発） 78 ( 2 ) I_571 - I_576 2022年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
土にセメントを添加するとセメント水和物が間隙を充填するため，その透水性は未処理時に比べて著しく減少する．しかしながら，最近では海水の化学的浸食によってセメント水和物が崩壊することが指摘されている．そのため，海水が浸透すると固化処理土の透水性が変化することが懸念される．本研究では，セメント処理した砂質土に海水の代用としてMg水溶液を通水し，透水性の変化を調べた．その結果，セメント処理土の透水性は著しく低下することが明らかになった．併用した各種機器分析の結果から，Mg水溶液の浸透によるセメント処理土の透水性の低下は，処理土に浸透したMg塩によってセメント水和物の崩壊や水酸化マグネシウムの析出が起こり，通水前に比べて間隙容積が減少するとともに，浸透しにくい小さな径の間隙が増加したためと推定された．
-
Koyama A., Fujimoto T., Suetsugu D., Fukubayashi Y.
Geomatics, Natural Hazards and Risk 13 ( 1 ) 1849 - 1866 2022年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Geomatics, Natural Hazards and Risk
Many heavy rain disasters have occurred in recent years in Japan. The maintenance of water storage facilities such as dams has become a global issue. The aim is to simulate the failure mechanism of reservoirs in which slip failure occurred on the downstream slope of the embankment due to the heavy rainfall in August 2019 in Japan. This study proposes a simulation method for evaluating embankment stability with respect to the fluctuations in the water level and the rainfall infiltration from the embankment surface using the two-dimensional saturated–unsaturated seepage flow simulation based on the finite element method. Moreover, the safety factors of the slip surface during heavy rain were calculated based on the simulated seepage line. By considering rainfall infiltration, the safety factor of the slip surface decreased significantly, and the occurrence of slip failure in the in-situ position could be reproduced. In conclusion, rainfall infiltration must be considered when evaluating the stability of a reservoir body during heavy rainfall.
-
Dynamic properties of rigid polyurethane foam in cyclic triaxial tests 査読あり
Koyama A., Suetsugu D., Fukubayashi Y.
International Journal of GEOMATE 20 ( 82 ) 34 - 39 2021年6月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of GEOMATE
The aim of this study is to clarify the dynamic properties of rigid polyurethane foam. A method for renovating a deteriorated bridge as a lightweight embankment was proposed. The space underneath a bridge is filled with polyurethane to support the upper structure. In this case, the upper structure of the bridge is considerably heavier than the polyurethane. Therefore, it is important to examine the seismic behavior of this new lightweight embankment. However, the dynamic deformation characteristics of polyurethane have not been clarified previously. In this study, stress-controlled cyclic triaxial tests based on JGS0542-2009 are used to evaluate the effect of the confining stress and the presence of a rigid layer on the dynamic properties of rigid polyurethane foam. As a result, the shear modulus of rigid polyurethane foam increases with increasing confining stress regardless of the absence of the rigid layer. The shear modulus of polyurethane with the rigid layer is lower than that of polyurethane without the rigid layer. The value of shear modulus of rigid polyurethane foam was measured in the range of approximately 1.6~3.2MPa. Moreover, the stiffness degradation and of rigid polyurethane foam are in good agreement with the Hardin-Drnevich model.
-
Reconnaissance report on geotechnical damage caused by a localized torrential downpour with emergency warning level in Kyushu, Japan 査読あり
Toshifumi Mukunoki, Daisuke Suetsugu, Kazunari Sako, Satoshi Murakami, Yoshinori Fukubayashi, Ryohei Ishikura, Takenori Hino, Satoshi Sugimoto, Kota Wakinaka, Shinichi Ito, Atsushi Koyama
Soils and Foundations 61 ( 2 ) 600 - 620 2021年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
-
令和2年7月九州豪雨による地盤災害特集号の追加報告について 査読あり
椋木 俊文, 末次 大輔, 酒匂 一成
地盤工学会災害調査論文報告集 1 ( 3 ) 333 - 333 2023年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 地盤工学会
本号は，令和5年4月1日に発刊された「地盤工学会災害調査論文報告集」創刊号の追加号である。「地盤工学会災害調査論文報告集」創刊号は，災害連絡会議から依頼を受けた企画であり，「令和2年7月九州豪雨による地盤災害調査報告書<sup>1)</sup>」をひな形にして，同災害の実態をアーカイブするための特集号として編集したものである。この調査報告書を作成した災害調査団の活動期間および報告集編集期間は，コロナ禍の状態であり，調査団間の連絡はメールが中心となった。また，越県調査も禁止していたため，調査団内に福岡-大分，長崎-佐賀，熊本-宮﨑-鹿児島の3つ領域ワーキンググループを作り，活動いただいた。調査団の中には，若手の研究者もいたことから，今後調査結果を論文発表したい可能性もあることを考慮し，この報告論文集への投稿については，あくまで調査団の意向ではなく各報告書の著者によるものとして公募した。ところが，一部で団員のメールアドレスが欠落していたことに気が付かれないまま，この企画が進められ，結果的に調査団員全員にこの方針がいきわたっていなかったことが，調査論文報告発刊後に判明した。本調査論文報告集の作成の意図が，調査結果を関係者の多くの方々に閲覧いただき，今後に役立ててもらうことが趣旨であることから，追加報告という形でも報告すべきであるという結論に至り，このような形で発刊させていただくこととした。今後の調査論文報告集については，調査団内での公募体制と形式を整えていただき，同様のことが起きないように留意いただきたい。最後に，追加発刊のためにご協力いただいた関係皆様には改めて御礼を申し上げる。
-
令和2年7月九州豪雨による地盤災害特集号の発刊に際して 査読あり
椋木 俊文, 末次 大輔, 酒匂 一成, 若井 明彦
地盤工学会災害調査論文報告集 1 ( 1 ) 169 - 169 2023年
-
神山 惇, 末次 大輔, 福林 良典
Construction and Building Materials 321 126377 2022年
-
降雨浸透を考慮したため池堤体のすべり破壊に対する安定性評価手法の検討
宮崎睦士，神山 惇，末次大輔，福林良典，藤本哲生
令和2年度土木学会西部支部研究発表会 2021年3月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
粘土地盤に打設された丸太継杭の鉛直支持力に及ぼす杭形状の影響
那須龍斗，末次大輔，神山 惇，福林良典
令和2年度土木学会西部支部研究発表会 2021年3月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
山腹のゆるみを形成する断裂構造の事例的考察
平田洋士，西内浩二，中島 渓，吉村辰朗，末次大輔
令和2年度土木学会西部支部研究発表会 2021年3月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
粘性土中に打設される木杭の鉛直支持力に及ぼす杭形状の影響 査読あり
末次 大輔, 那須 龍斗, 神山 惇, 福林 良典
土木学会論文集E2（材料・コンクリート構造） 77 ( 5 ) I_77 - I_83 2021年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
粘性土地盤における木杭の極限支持力は末口径を直径とする円柱体の周面抵抗力で評価される．木杭は元来テーパー形状であり，単体あるいは継いで使用されるので，テーパー角や継ぎ部の形状が支持力に影響を及ぼすことが考えられる．本研究では同一末口径のストレート形状およびテーパー角が異なる4種類の一本杭と，2種類の継杭の模型木杭を用い，粘性土中における木杭の鉛直載荷試験を行って，木杭形状が鉛直支持力と周辺地盤の状態変化に及ぼす影響ついて検討した．粘土中の木杭の鉛直支持力はテーパーを有すると大きくなること，継杭では上下杭接合部において杭と周辺粘土との非接触領域が増加すると鉛直支持力が低下することを明らかにした．さらに，木杭は杭周辺の粘土の含水比を低下させる効果を有することを確認した．
-
カルシウム溶脱を受けたセメント処理粘土のせん断強度特性 査読あり
末次大輔，井上徹郎，原弘行
第14回地盤改良シンポジウム論文集 79 - 82 2020年12月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
一面せん断試験による発泡ウレタンとコンクリートの境界面におけるせん断強度特性 査読あり
神山惇，末次大輔，福林良典，三田部均
ジオシンセティックス論文集 35 141 - 148 2020年11月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
令和元年8 月豪雨によって決壊した佐賀県小城市におけるため池の被災メカニズムに関する一考察 査読あり
神山惇，藤本哲生，末次大輔
自然災害科学 ( 特別 ) 33 - 44 2020年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
塩水浸透劣化に伴うセメント処理土の強度特性の変化
井上徹郎，末次大輔
第55回地盤工学研究発表会講演概要集 2020年7月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
同時充填工法による土留め部材の引抜時の周辺地盤の変形解析手法の検討
武内大晋, 福林良典, 神山惇, 末次大輔, 渡辺広明, 山下大地, 児玉寛太郎
第55回地盤工学研究発表会 2020年7月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
実物大走行実験による土のう路盤の荷重分散効果の検討
佐藤聡平, 福林良典, 神山惇, 末次大輔
第55回地盤工学研究発表会 2020年7月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
FEM 解析による橋梁下部空間に充填された発泡ウレタンの応力分布および変位量の検討
村上 遼, 神山惇, 福林良典, 末次大輔, 審良善和, 三田部均
第55回地盤工学研究発表会 2020年7月
記述言語：日本語 掲載種別：研究論文（研究会，シンポジウム資料等）
-
令和元年8月豪雨による佐賀県小城市のため池被害調査報告 査読あり
神山惇，藤本哲生，工藤啓幹，末次大輔
自然災害科学 39 ( 2 ) 83 - 87 2020年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
土試料の最大粒径に着目した小型締固め試験装置による締固め試験方法の検討 査読あり
神山 惇, 福林 良典, 末次 大輔, 鈴木 素之
地盤工学ジャーナル 15 ( 1 ) 91 - 102 2020年3月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 地盤工学会
土構造物の健全性を評価する上で，その締固め度を把握することは極めて重要である。本研究は，締固め試験の効率化を目的とし，従来の締固め試験で用いられる内径10cmおよび15cmのモールドよりも小さい内径5cmの小型モールドと，小型ランマーを用いた締固め試験方法の確立を目指すものである。本論文では，5cmモールドにおける許容最大粒径および，最大粒径とその次に大きい粒径の間に入る土粒子の含有率が締固め特性に及ぼす影響を検討した。その結果，5cmモールドの許容最大粒径は9.5mmであることがわかった。また，既往の礫補正式（W&H式）を用いて，粒径9.5mm以上の礫粒子を含む土試料の最大乾燥密度の算出を検討した結果，礫粒子の含有率が30%以内であれば，最大乾燥密度の実測値と補正値の相違率は2%以内であった。
DOI： 10.3208/jgs.15.91
-
Numerical Analysis for Earthquake Resistance of Retaining Wall Using Gabions 査読あり
Tsuyoshi Nishi, Tadashi Hara, Hiroshi Nakazawa, Daisuke Suetsugu
EPI International Journal of Engineering 2 ( 2 ) 116 - 126 2020年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
-
Basic Study on Deformation Evaluation of Steel Wire Mesh for Rational Gabion Structure Design 査読あり
Hiroshi Nakazawa, Tsuyoshi Nishi, Hiroyuki Kurihara, Daisuke Suetsugu, Tadashi Hara
EPI International Journal of Engineering 2 ( 2 ) 109 - 115 2020年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
-
A biomediated deterioration mitigation method for cement-treated soil 査読あり
Hata T., Suetsugu D., Kasama K.
Environmental Geotechnics 7 ( 6 ) 435 - 444 2020年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Environmental Geotechnics
Cement-treated soil is widely used in many countries and is sometimes applied in estuary and coastal region civil infrastructures such as embankments and port facilities. In some of these facilities, leachates and deterioration of strength have been detected after 20 years of service and therefore require maintenance work such as chemical injection and reconstruction. The reasons for these failures could be the elution of calcium ions from calcium chloride (CaCl2) in cement-treated soil. The main objective of the present research project was to propose biobased deterioration mitigation techniques that can independently recrystallise calcium ion eluates to calcite in cement-treated soil and thereby maintain operational conditions and long-term use of infrastructures. The mechanisms of calcite recrystallisation focused on microbial-induced calcite precipitation (MICP) under high pH conditions (pH ≈ 9·0), which was confirmed in laboratory tests. The main outcome of this research is that application of the MICP process to cement-treated soil can maintain operational conditions and can mitigate deterioration by simple addition of chemicals during the mixing phase.
-
令和元年8月豪雨による佐賀県小城市のため池被害調査報告 査読あり
神山 惇, 藤本 哲生, 工藤 啓幹, 末次 大輔
自然災害科学 39 ( 2 ) 83 - 88 2020年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本自然災害学会
令和元年 8 月の豪雨では，主に佐賀県および長崎県を中心とした九州北部各地で観測史上1位となる雨量が観測された。福岡県および佐賀県では複数のため池が被災した。佐賀県においては，佐賀市，小城市，武雄市，鳥栖市等で20箇所のため池の被災が報告されており，小城市では 1 箇所のため池が決壊している。本報では，被災報告のあった佐賀県小城市におけるため池の被害状況について調査した結果を報告する。
-
令和元年8月豪雨によって決壊した佐賀県小城市におけるため池の被災メカニズムに関する一考察 査読あり
神山 惇, 藤本 哲生, 末次 大輔
自然災害科学 39 ( S07 ) 33 - 43 2020年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本自然災害学会
令和元年8月の豪雨では，福岡県および佐賀県で複数のため池が被災した。本研究では，佐賀県小城市において決壊した西分第1ため池の被災メカニズムを明らかにすることを目的とし，合理式法に基づいた堤体の越流発生の有無の判定および降雨浸透を考慮した堤体下流法面の安定性を検討し，ため池が決壊した要因の分析を行った。FEM 解析による非定常の飽和- 不飽和浸透流解析を行い，同時に修正フェレニウス法による堤体法面の安定解析を行った。その結果，
降雨浸透によって堤体下流法尻にすべり破壊が発生し，堤体が不安定化したことで，上流側に向かってすべり破壊が進行したことが主な要因と推察される。 -
カルシウム溶脱を受けたセメント処理粘土のせん断強度特性 査読あり
末次 大輔
第14回地盤改良シンポジウム論文集 14 79 - 82 2020年
掲載種別：研究論文（学術雑誌）
-
一面せん断試験による発泡ウレタンとコンクリートの境界面におけるせん断強度特性 査読あり
神山 惇, 末次 大輔, 福林 良典, 三田部 均
ジオシンセティックス論文集 35 ( 0 ) 141 - 148 2020年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：国際ジオシンセティックス学会 日本支部
近年の技術者不足や高額な維持管理費用のために，橋梁の維持管理の脆弱化が課題となっている．筆者らは，老朽化橋梁の維持管理技術の一つとして，橋梁の下部空間に軽量盛土材である発泡ウレタン（以降、ウレタン）を吹付け充填し，老朽化橋梁を軽量盛土に更新する工法の確立を目指している．本研究では，ウレタンの接着力を明らかにすることを目的とし，ウレタンとコンクリートとの境界面において一面せん断試験を行い，その境界面のせん断強度特性を調べた．その結果，ウレタンとコンクリートの接着面においては，初めにウレタンがせん断箱で圧縮せん断され，せん断変位が30mm付近に到達するとウレタンがコンクリートから剥離した．ウレタンとコンクリートの境界面のせん断強度は，垂直応力の影響を受けることがわかった．
-
Nakazawa H., Usukura K., Hara T., Suetsugu D., Kuribayashi K., Nishi T., Kimura S., Shimomura S.
Journal of Disaster Research 14 ( 9 ) 1154 - 1169 2019年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Disaster Research
© 2019, Fuji Technology Press. All rights reserved. The earthquake (Mw 7.3) that struck Nepal on April 25, 2015 caused damage to many civil engineering and architectural structures. While several road gabion retaining walls in mountainous regions incurred damage, there was very little information that could be used to draw up earthquake countermea-sures in Nepal, because there have been few construction cases or case studies of gabion structures, nor have there been experimental or analytical studies on their earthquake resistance. Therefore, we conducted a shake table test using a full-scale gabion retaining wall to evaluate earthquake resistance. From the experiments, it was found that although gabion retaining walls display a flexible structure and deform easily due to the soil pressure of the backfill, they are resilient structures that tend to resist collapse. Yet, because retaining walls are assumed to be rigid bodies in the conventional stability computations used to design them, the characteristics of gabions as flexible structures are not taken advantage of. In this study, we propose an approach to designing gabion retaining walls by comparing the active collapse surface estimated by the trial wedge method, and the experiment results obtained from a full-scale model of a vertically-stacked wall, which is a structure employed in Nepal that is vulnerable to earthquake damage. When the base of the estimated slip line was raised for the trial wedge method, its height was found to be in rough agreement with the depth at which the gabion retaining wall deformed drastically in the experiment. Thus, we were able to demonstrate the development of a method for evaluating the seismic stability of gabion retaining walls that takes into consideration their flexibility by adjusting the base of the trial soil wedge.
-
In situ characteristics of bottom sediment in Ichkeul Lake, Tunisia 査読あり
Daisuke Suetsugu, Toshiro Hata, Mitsuteru Irie, Taichi Tebakari, Atsush iKawachi
Euro-Mediterranean Journal for Environmental Integration 4 ( 1 ) 35 2019年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
The supply of sediment to Ichkeul Lake has decreased due to the construction of several reservoirs in the upstream reaches of the rivers that flow into it. Furthermore, it is necessary to control lake sediment outflow in order to preserve the ecological balance of the lake. Soil stabilization methods could be used to prevent the erosion of bottom sediment. Therefore, this study explored the physical and mechanical condition of the lake bed in situ to aid the identification of an effective erosion prevention scheme based on solidification methods. Two locations on the lake bottom were investigated and compared: one where the sediment dried up in summer, and the other where the sediment was saturated with water throughout the year. Undisturbed samples were collected using a thin-walled stainless steel tube sampler. The shear strength and its depth distribution in the lake bed were measured using the vane shear test. The depth distributions of the shear strength at the two sampling locations studied were found to be rather different. The shear strength was highest in the surface layer at the location that was dry in summer, whereas the shear strength was lowest in the surface layer at the location that was always wet. The shear strength of the surface layer (20 mm depth) at the wet/dry location was 3.3 kPa and there was 93.1% moisture, while the shear strength at this depth at the permanently wet location was 1.8 kPa and there was 95.7% moisture. The strength of the wet/dry sediment, which underwent shrinkage when drying, was greater than that of the permanently wet sediment. This finding could facilitate the classification of areas that require soil improvement as well as the rational design of an erosion prevention plan.
-
The effect of fracture zones on a failed reinforced soil wall induced by severe ground motions during the 2016 Kumamoto Earthquake 査読あり
K. Sahara, D. Suetsugu, N. Fukuda, T. Yoshimura, H. Sato, F. Hirae
Proc. of the 16th Asian regional conference on soil mechanics and Geotechnical engineering 2019年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
-
感潮河川に堆積する高含水比浚渫土を用いた解砕固化処理土の締固め特性と耐侵食性 査読あり
井上徹郎、末次大輔
第13回環境地盤工学シンポジウム 発表論文集 433 - 436 2019年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
Toshiro Hata, Daisuke Suetsugu, Atsusi Kawachi, Mituteru Irie
Euro-Mediterranean Journal for Environmental Integration 4 ( 1 ) 2019年7月
記述言語：英語 掲載種別：研究論文（学術雑誌）
Ichkeul Lake in northern Tunisia is a UNESCO World Heritage site. During the 1990s, its role as a nesting site for birds migrating between Europe and Africa became less prominent due to the increase in salinity due to the inflow of seawater from the Bay of Bizerte. This seawater inflow with increasing saline concentration was enhanced by lake-bed subsidence due to a reduction in sediment supply as a result of reservoir development. This phenomenon occurred by decreasing lake-bed elevation, which was accelerated by the draining from Ichkeul Lake to the Bay of Bizerte, with the resuspension of lake-bed sediments due to wind disturbance. In this study, self-medicating granular geomaterial with in situ microorganisms was proposed to raise or maintain the lake-bed elevation. This geomaterial can enhance urease-producing bacterial activity in the lake and accelerate calcite precipitation onto the surface of the lake bed, thus improving the benthos’ living conditions. Further, nitrogen resources are released from this geomaterial, which enhances the lake ecosystem by promoting aquatic plant growth. Filed column exposure tests were conducted to evaluate the proposed method’s effectiveness. Results were as expected. Therefore, this new geomaterial should help restore the function of Ichkeul Lake as a habitat for migratory birds while also recovering lake-bed elevation and aquatic plant conditions.
DOI： s41207-019-0111-3
-
Experimental evaluation on earthquake-resistance of road retaining wall using gabion 査読あり
H. Nakazawa, T. Hara, D. Suetsugu, T. Nishi, K. Kuribayashi
Journal of Disaster Research 13 ( 5 ) 897 - 916 2018年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
-
A Bio-Mediated Deterioration Mitigation Method for Cement-Treated Soil 査読あり
T. Hata, D. Suetsugu, K. Kasama
Journal of Environmental Geotechnics 2018年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
-
蛇籠を用いた道路擁壁の耐震性評価に関する実大規模振動台実験 査読あり
中澤 博志, 原 忠, 末次 大輔, 栗林 健太郎, 西 剛整, 三好 克明, 田所 佑理佳, 臼倉 和也
土木学会論文集A1（構造・地震工学） 74 ( 4 ) I_441 - I_451 2018年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
2015年ネパール・ゴルカ地震における蛇籠被害の実態調査と耐震性向上に向けた具体策の検討 査読あり
原 忠, 中澤 博志, 末次 大輔, 栗林 健太郎, 西 剛整, 田所 佑理佳, 三好 克明, 張 浩
土木学会論文集A1（構造・地震工学） 74 ( 4 ) I_586 - I_597 2018年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
Geotechnical utilization of sand with waste expanded polystyrene 査読あり
Yasufuku N., Ochiai H., Omine K., Suetsugu D.
ISRM International Symposium 2000, IS 2000 2018年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：ISRM International Symposium 2000, IS 2000
Waste disposal has become a serious problem because of lack of land-fill and it should be solved urgently. It is therefore desirable to develop an effective method of geotechnical treatment to use the waste materials. The waste expanded polystyrene (EPS), which is widely obtained in Japan, may be utilized as a material for lightening by mixing with soil. The aim of this study is to investigate the compression and direct shear properties of a mixture of sand and heat compressed and crushed EPS (HCCE) for possible use as a light weight fill material. The test results showed that the HCCE material was effective to lighten the self-weight of soil and also to increase the shear strength of geomaterial. In addition, the sand mixed with the HCCE material was found to be a useful fill material on soft ground based on the results of the slope stability analysis.
-
An issue of seismic structure and construction regarding gabion retaining wall in rural areThe 7th Asia Conference on Earthquake Engineeringa of Nepal 査読あり
Kimura, S., Hara, T., Suetsugu, D., Nakazawa, H., Nishi, T., Shimomura, S., Shibahara, R. and Kuribayashi, K.
2018年
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
-
木材の含水率がピロディン試験値とドライバーの貫入深さに及ぼす影響 査読あり
山田昌郎，原忠，水谷洋介，三村佳織，沼田淳紀、末次大輔 他
木材利用研究論文報告集 16 63 - 70 2017年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
-
Residual deformation in Full-scale shake table test of a gabion retaining wall for road 査読あり
Hiroshi Nakazawa, Tadashi Hara, Daisuke Suetsugu, Kentaro Kuribayashi, Tsuyoshi Nishi and Hemanta Hazarika
2017年8月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス）
-
海水曝露した石灰処理土の表面に生成される白色析出物とその劣化抑制効果 査読あり
原 弘行, 末次 大輔, 松田 博, 亀井 健史
土木学会論文集C（地圏工学） 73 ( 2 ) 224 - 232 2017年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
固化処理土は海水に曝露するとその表面において，白色の析出物が生じる場合がある．本研究では，粘性土試料を母材とした石灰処理土に対して，海水を模擬したマグネシウム水溶液への浸漬実験を実施し，処理土表面に生成される析出物について観察・分析を行うとともに析出物生成の有無による石灰処理土のカルシウム溶出挙動および力学的劣化状況の差異を検討した．その結果，比較的石灰添加量が多いケースで処理土表面に析出物の生成が確認された．この析出物は球体状の水酸化マグネシウムと推定され，その緻密な構造によって処理土からのカルシウムの溶出，ひいては力学的劣化の進行を抑制する効果を持つことを示した．
-
マグネシウム塩を含有する石灰・セメント処理土の強度発現および海水環境下での劣化速度 査読あり
原 弘行, 末次 大輔, 松田 博, 亀井 健史
土木学会論文集C（地圏工学） 72 ( 4 ) 294 - 299 2016年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
石灰やセメントを混合した地盤の強度発現には種々の要因が関係しており，とくに粘土鉱物の種類や間隙水の性質によっては著しく強度発現が阻害される場合がある．本研究では，マグネシウム塩を含む粘性土試料を母材とした石灰・セメント処理土の強度特性を調べるため，マグネシウム塩の濃度を変化させた処理土に対して一軸圧縮試験を実施した．つぎに，同様の処理土に対して海水環境を想定した劣化促進実験を行い，力学的劣化の進行に及ぼすマグネシウム塩の影響を考察した．その結果，処理土内のマグネシウム塩は強度発現を阻害するとともに，劣化の進行を促進させることを示した．また，固化処理土に含まれる酸化カルシウム量とそのマグネシウム塩との比率に着目し，固化材の種類に依存しない劣化速度の評価指標を提案した．
-
微生物機能を活用したセメント改良土の劣化抑制技術に関する検討 査読あり
三原 一輝, 末次 大輔, 笠間 清伸, 畠 俊郎
土木学会論文集B3（海洋開発） 72 ( 2 ) I_414 - I_419 2016年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
近年，セメントを用いた固化処理工法が盛んに利用されているが，セメント改良土は海水に接触すると，固化成分であるカルシウム（Ca）が海水中に溶出し劣化することが既往の研究から明らかになっている．そこで，本研究では，海水曝露条件下における劣化と温度の関連を明らかにするとともに，微生物由来の尿素加水分解酵素を利用し，セメント改良土から溶出するCa分をCaCO<sub>3</sub>としてセメント改良土中に再固定する新しい劣化抑制技術について検討した．試験の結果から，セメント改良土は海水曝露される温度条件が高いとより劣化が促進されること，微生物機能を利用すると温度条件に関わらずCaの溶出を抑制することが明らかとなった．以上より，セメント改良土の海水環境下での劣化抑制技術として微生物機能の併用が有効であると考えられる．
-
末次 大輔, 原 弘行
低平地研究 = Research on lowland technology ( 24 ) 24 - 28 2015年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：低平地研究会
-
Change of mechanical properties of the cement mixed marine clay under seawater 査読あり
Suetsugu D., Hara H., Manandhar S.
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability 1128 - 1131 2015年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability
This paper focuses the mechanical properties of the deteriorated cement mixed marine clay when immersed in seawater. Series of shear box tests were conducted maintaining the constant volume for the deteriorated cement mixed Ariake clay. The deteriorated specimen was prepared immersing into the artificial seawater simulated in the laboratory for 630 days. Authors compared the change in mechanical properties of the deteriorated specimen with the non-deteriorated cement mixed clay together with remolded Ariake clay. The deterioration of specimens with intrusion of simulated seawater increases compressibility which is associated entirely with the presence of cement at the beginning of the experiment. The deterioration decreased the shear strength of the cement mixed marine clay. The strength of deteriorated cement mixed marine clay dissolved by calcium is almost equal to that of the remolded Ariake clay.
-
海水曝露によって劣化した石灰処理土の間隙径分布と圧密特性 査読あり
原 弘行, 末次 大輔, 松田 博
土木学会論文集C（地圏工学） 71 ( 3 ) 177 - 190 2015年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
石灰・セメント処理した粘性土は，海水環境下においてカルシウム成分の溶出が促進され，力学的に劣化することが示されている．本研究では，石灰処理土を対象に，劣化の進展に伴う間隙径分布の変化ならびに劣化した処理土の圧密特性を調べることを目的として，海水浸漬により劣化した処理土と未浸漬の処理土に対して間隙径分布の測定と圧密試験を実施した．その結果，劣化した石灰処理土は間隙の総量をほぼ一定に保った状態で比較的大きな径の間隙が増加し，石灰混合履歴を持たない母材の粘性土に類似した間隙径分布へ遷移することを示した．また，劣化した処理土の圧縮性は海水浸漬前に比べて大きくなることを示し，その原因は処理土のセメンテーション効果の解消だけでなく，骨格の変化が生じやすい間隙径分布に変化したことも影響していると推定した．
-
Manandhar S., Suetsugu D., Hara H., Hayashi S.
Lowland Technology International 16 ( 2 ) 81 - 88 2014年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Lowland Technology International
Full scale field experimentations were incorporated along the downstream of the Chikugo River, Saga, Japan in order to observe the effect of wooden raft and pile foundation on the soft clay. In this study, the wooden raft and pile foundation was utilised for the marginal strip to understand the disposition of vertical settlements and lateral displacements of the ground. Cypress wood was taken into consideration in order for constructing raft and pile. Two different types of wooden raft and pile foundations with same dimensions were installed in the ground. The wooden raft installed with single-sided assemblages of wooden piles was configured as Case I. While, the same raft with both-sided assemblages of wooden piles was configured as Case II. A new embankment was constructed embedded with the existed ones on the river dike. The study was carried out for 136 days span of time from the beginning of the embankment construction. The results showed that both side assemblages of wooden piles were more effective to prevent the lateral displacement, reduce the vertical settlement and local deformation of the dike and the surrounding ground with compared to the single-sided installed piles of the similar foundation structure. The test results confirmed that the river dike supported by the wooden raft and pile foundation can be anticipated as more stable on sand layer of the soft ground within the depth of pile length.
DOI： 10.14247/lti.16.2_81
-
海水環境下におけるセメント処理した有明粘土の劣化の進行に関する検討 査読あり
原 弘行, 末次 大輔, 林 重徳, 松田 博
材料 63 ( 1 ) 49 - 54 2014年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本材料学会
In construction, chemical soil stabilization method, such as adding cement and quick lime has been often applied to increase the strength of soft ground and surplus soil. However, in some specific natural environments, such a stabilization method may cause significant reduction of the strength of treated-soil. In this paper, Ordinary Portland cement was used as a stabilizer for examining the durability of chemical stabilized Ariake clay under seawater condition. In order to prepare deteriorated specimens, original Ariake clay was mixed with different contents of cement (50, 70, 100kg/m<sup><font size="-1">3</font></sup>) and immersing artificial seawater with different NaCl concentration (10, 20, 30g/L). The deterioration progress of cement-treated Ariake clay was investigated by using the micro cone penetration test. It is shown from the test results that the deterioration of cement-treated soil progresses in proportion to square root of seawater contacting duration. In addition, an empirical prediction formula of deterioration rate of cement-treated Ariake clay considering effect of Mg ion concentration in seawater and water-cement ratio in the treated soil is proposed according to experimental results.
DOI： 10.2472/jsms.63.49
-
Hazarika H., Kasama K., Suetsugu D., Kataoka S., Yasufuku N.
Indian Geotechnical Journal 43 ( 2 ) 137 - 152 2013年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Indian Geotechnical Journal
The 2011 off the pacific coast of Tohoku Earthquake and the associated tsunami brought disaster to many soil structures. This paper summarizes the investigation results of waterfront structures in the northern area of Tohoku region (Aomori prefecture and northern Iwate prefecture). The investigations focused on the geotechnical and structural aspects of the damages to coastal dikes, quay walls and breakwaters due to the earthquake and the tsunami as well as the backrush. Analyses of the damage and their nature indicate that, in the north of Tohoku, rather than the earthquake itself the compound disaster brought by the tsunami was more rampant. The investigations reveal that the force of tsunami, the force of overtopping tsunami and the force of backrush were responsible for the scouring of the mound of breakwaters and seawalls resulting in the catastrophic failure of such structures. © 2012 Indian Geotechnical Society.
-
海水に曝露したセメント処理土の劣化機構に関する基礎的研究 査読あり
原 弘行, 末次 大輔, 林 重徳, 松田 博
土木学会論文集C（地圏工学） 69 ( 4 ) 469 - 479 2013年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
本論文は，海水に曝露したセメント処理土の劣化機構について溶出試験結果および海水浸漬試験結果をもとに考察したものである．セメント処理土のカルシウムの溶出は，海水中のマグネシウムを含む塩が間隙水のpHを低下させ，溶解度が増加することによって生じることを示した．さらに，海水に最長1年間浸漬したセメント処理土の内部性状を経時的に調べ，マグネシウムの影響によるカルシウムの溶出現象を確認し，処理土のカルシウム濃度の減少がセメンテーション物質の崩壊を招き，力学的に劣化することを推定した．
-
間隙径分布の変化からみた海水浸漬した固化処理土の劣化機構 査読あり
原 弘行, 末次 大輔, 林 重徳
低平地研究 = Research on lowland technology 0 ( 21 ) 31 - 36 2012年5月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：佐賀大学低平地防災研究センター
-
青森県・岩手県北部における地震と津波による複合地盤災害 査読あり
ハザリカ へマンタ, 片岡 俊一, 笠間 清伸, 金子 賢治, 末次 大輔
地盤工学ジャーナル 7 ( 1 ) 13 - 23 2012年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 地盤工学会
東北地方太平洋沖地震は，その地震動および津波によって東日本の広範囲で甚大な被害をもたらした。本論文は，青森県三八上北地方および岩手県北部において発生した地盤災害に対しての調査結果をまとめたものである. 調査地域の範囲内では地震そのものより複合性のある被害（例：津波による地盤災害や液状化による被害など）が顕著であった. 本論文では, 特に地震動, 押し波, 引き波および構造物の構造形式などを着眼とした太平洋沿岸部の被害について述べる.
DOI： 10.3208/jgs.7.13
-
原 弘行, 末次 大輔, 林 重徳
材料 61 ( 1 ) 11 - 14 2012年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 日本材料学会
The lime and the cement treated soil have been regarded as stable for a long time due to hydrate generated by pozzolanic reaction. As the treated soil is exposed to natural conditions, its strength would decrease by calcium leaching. In lowland having the thick alluvial clay deposit, the chemical soil treated method is often applied to improve the strength of soft clay ground. The lime treated soil applied to the base of a tidal river dike is deteriorating. It had been constructed in about twenty years ago and now appears to be muddy and leakage of river water. The treated soil is exposed to seawater in this area. This study considered mechanism of calcium leaching from the lime treated soil when it was immersed in seawater. Leaching tests were carried out to clear influences of the component of seawater on calcium leaching. Artificial seawater, NaCl, MgCl<sub><font size="-1">2</font></sub>, MgSO<sub><font size="-1">4</font></sub> solutions were used in the test. Influence of NaCl on calcium leaching was very small. Magnesium containing in seawater reduced pH value of the solution-treated soil mixture. Calcium leaching was accelerated when magnesium concentration was higher. Magnesium was founded to be a main component to cause calcium leaching.
DOI： 10.2472/jsms.61.11
-
改良土(力学特性)(1)(3.地盤材料,総括,<特集>第47回地盤工学会研究発表会) 査読あり
末次 大輔
地盤工学会誌 60 ( 12 ) 2012年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：地盤工学会
-
海水に浸漬した石灰処理土の特性変化に及ぼす含水比の影響 査読あり
原 弘行, 末次 大輔, 林 重徳
低平地研究 ( 20 ) 21 - 24 2011年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：佐賀大学低平地防災研究センター
-
改良土の力学特性(3.地盤材料,総括,<特集>第46回地盤工学研究発表会) 査読あり
末次 大輔
地盤工学会誌 59 ( 12 ) 2011年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：地盤工学会
-
Thermal environment of tidal mud of Ariake Sea 査読あり
Moqsud M., Hayashi S., Suetsugu D., Bushra Q.
Lowland Technology International 12 ( 2 ) 34 - 41 2010年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Lowland Technology International
A remarkable decrease of catch of shells was observed during the last three decades in the Ariake Sea, Japan. The higher content of acid volatile sulfide (AVS) is responsible for the unfavorable geo-environmental condition of the Ariake Sea. This paper presents an assessment of the thermal environment of the Ariake Sea tidal flat as a part of geo-environmental condition study. To observe the daily and seasonal variation of temperature in different depths, temperature was measured by inserting the thermocouple at various specified depths and at 0.10 m depths interval in the last week of every month at study areas in the Ariake Sea tidal flat, respectively. Thermal properties of the sea mud were measured by using the thermal properties analyzer (KD2). It was observed that during spring and summer heat was transferred from subsurface to the deeper depth however during winter and autumn the opposite phenomena happened. This type of temperature profile in the tidal flat helps to enter the sea laver treatment medicine during winter and consequently deteriorate the mud and again helped to increase remediation of the Ariake sea tidal mud naturally during summer.
-
Performance of raft & pile foundation on soft ariake clay ground under embankment loading 査読あり
Poungchompu P., Hayashi S., Suetsugu D., Du Y.J., Alfaro M.C.
Lowland Technology International 12 ( 1 ) 41 - 46 2010年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Lowland Technology International
Road constructions are being planned along the Ariake Sea Gulf of Japan. This paper proposes a new foundation method for an embankment on soft subsoil by using high durability and non-polluting materials. Recently, the global warming is progressing. To address the problem of the global warming, using a lot of wood as construction material and making a forest active are one of the problems to be solved. Field investigation has shown that even after more than one thousand years, brush wood reinforcement under the Mizuki embankment in north Kyushu, Japan; still have high durability with under water table condition. In this study, a series of laboratory model tests and finite element analysis were carried out to investigate the effectiveness of Raft & Pile method for soft ground improvement for construction of highway embankments on soft Ariake clay. Results can be investigated thatembankment loading on the soft Ariake clay without any extra ground support large settlement and large deformation occur. With Raft & Pile settlement and deformation in soft ground was reduced significantly.
-
Dynamic response of nailing-reinforced earthen Kiln-Dougaeri No.2 to an earthquake 査読あり
Chai X.J., Hayashi S., Suetsugu D., Moqsud M.A.
Lowland Technology International 12 ( 1 ) 23 - 29 2010年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Lowland Technology International
Soil nailing was used to strengthen a historical earthen kiln based on static analysis without considering earthquake loads in reinforcement design. The nailing-reinforced kiln experienced an unexpected earthquake and retained stable. In this study, the dynamic response of the nailing-reinforced structure to the real earthquake is presented and analyzed by finite element method (FEM) code-PLAXIS. First, the static stability analysis and the reinforcement design were re-evaluated, the analysis results by PLAXIS were consistent with the analysis preciously done by FLAC. Then, the time history of the ground acceleration of the real earthquake was applied to the model to perform dynamic analysis. The dynamic response was evaluated by analyzing the acceleration response, the mobilization of axial tensile force of nailing, development of yielding zone, variation of stress, and effect of dynamic frequency. The results indicated that the nailing-reinforced earthen kiln had good performance on dynamic loads from earthquake.
-
アゲマキの生息環境改善を目的とした大気圧密による干潟底泥の含水比低下の試み 査読あり
末次 大輔, 林 重徳, 牛原 裕司
低平地研究 ( 19 ) 29 - 36 2010年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：佐賀大学低平地防災研究センター
-
Moqsud M., Hayashi S., Bushra Q., Suetsugu D.
Journal of Environmental Informatics 15 ( 1 ) 42 - 46 2010年3月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Environmental Informatics
The Ariake Sea, which is one of the best-known semi-closed shallow seas in Japan, is famous for its various kinds of fisheries' products and seaweed cultivation. Recently, a dramatic decrease in the catch of shells has been observed in the Ariake Sea. This study discusses an innovative improvement method that was used in the tidal mud of the Ariake Sea to restore the Sinonovacula constricta shells. Field investigations were carried out in the Iida tidal flat area by creating an improvement area comprising of dikes, sand and recycled waste glass. Results indicate that in the improvement area, water content was reduced to less than 200% in the upper layers of the mud and compares favorably with the non-improvement area that had a water content of 250%. Additionally, the acid volatile sulphide (AVS) value in the improvement area declined significantly and was measured within the safe limit for both the benthos living in the tidal mud and the adult shells. © 2010 ISEIS All rights reserved.
-
海水環境下における石灰処理土の性状変化に関する基礎的検討 査読あり
原 弘行, 林 重徳, 末次 大輔, 水城 正博
土木学会論文集Ｃ 66 ( 1 ) 21 - 30 2010年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
本研究では，海水環境下における石灰処理土の性状の変化を明らかにすることを目的にして，石灰処理した有明粘土および濃度を変化させた人工海水を使用して，溶出試験と浸漬試験を実施した．その結果，石灰処理土と接触する人工海水の濃度が高いときほど，生石灰の主成分であるCaの溶出量が多くなることを明らかにした．また，人工海水に浸漬した石灰処理土は，浸漬水との接触面から深部に向かい，徐々に軟化することを示した．軟化がみられる範囲では石灰処理土中のCa濃度が著しく低下する．
DOI： 10.2208/jscejc.66.21
-
スラリー状で打設した石炭灰の強度特性と最適混合水量の評価法 査読あり
末次 大輔, 宮田 喜壽
土木学会論文集Ｃ 65 ( 3 ) 663 - 672 2009年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
石炭灰は混合水量によって，団粒状態，流動状態，分離状態を示す．本研究では混合水量の異なる3種類の石炭灰について三軸圧縮試験を行い，石炭灰の強度特性に及ぼす混合水量の影響を調べた．石炭灰の強度特性はスラリー作製時の状態の影響を受け，最大のせん断強度を発揮する混合水量が存在することが明らかになった．著者らが提案する石炭灰のコンシステンシー指標を用いると，その混合状態を合理的に推定できることを示す．そして，フォールコーン試験結果から最適混合比を簡便に評価できることを示す．
-
固化処理(物理化学変化)((9)固化処理・薬液注入,3.地盤材料,<特集>第44回地盤工学研究発表会) 査読あり
末次 大輔
地盤工学会誌 57 ( 12 ) 2009年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：社団法人地盤工学会
-
Calcium leaching properties of lime-treated soil by infiltration of tidal river water 査読あり
Hara H., Suetsugu D., Hayashi S., Du Y.J.
Proceedings of the International Offshore and Polar Engineering Conference 810 - 813 2008年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Proceedings of the International Offshore and Polar Engineering Conference
At present, the leakage is found in foundation of the dike constructed 20 years ago. The dike is constructed along the river in which directly connect to the Ariake Sea surrounded by a vast flat coastal area with very large tidal range. The Ariake clay and lime admixture were used as a main material for the foundation of the dike. The sludge material was found on the surface of lime-treated soil at the leaking point. This condition could weaken the treated soil in the foundation, and subsequently reduce the stability of the dike. In this study, in order to verify the cause of sludge materials leach from lime-treated soil, both water quality analysis in the field and two leaching test (solvent: NaCl and H O ) at the laboratory were performed. There is tendency of Ca leach from lime-treated soil due to the high concentration of NaCl and HH O solvent. The results indicated that the infiltration of tidal river water to the lime-treated soil induces increasing in the leaching of Ca in which could reduce the strength of the treated soil. Copyright © 2008 by The International Society of Offshore and Polar Engineers (ISOPE). 2 2 2 2 2+ 2+
-
Harianto T., Hayashi S., Du Y., Suetsugu D.
Water, Air, and Soil Pollution 194 ( 1-4 ) 141 - 149 2008年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Water, Air, and Soil Pollution
In the daily and final landfill cover barrier system, the hydraulic properties of compacted soil liners and the strength of soil can be adversely affected by desiccation cracking, resulting in the loss of effectiveness and integrity of the containment system as a barrier. Recently, there is an interest of using fiber additive to overcome the desiccation cracking problem. In this study, the desiccation crack test was conducted to investigate the effect of fiber additive on suppressing desiccation cracks in compacted Akaboku soils. Polypropylene (C H ) fiber was used as an additive material for soil sample. The percentages of fiber used were varied as 0.0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.2% (by dry weight of samples). The soil specimens were compacted under the conditions of maximum dry density and optimum water content. The surficial cracking area was measured to determine the crack intensity factor (CIF) of the soil samples. The desiccation crack test results indicated that the percentage of volume change of the compacted soil specimen decreased with addition of fiber. The change in the soil surface area decreased with increasing in the fiber content (FC), and consequently, the volumetric shrinkage strain decreased. The CIF for the soil without fiber (FC=0.0%) were significantly higher than the soil with fiber additive. The CIF of soil at FC=0.0% decreased from 2.75% to 0.6% for the soil at FC=0.2%. It was also found that the maximum crack depth reaches almost 50% of the thickness of the soil without fiber additive. This study suggests the potential application of the fiber additives to soils as an available method to suppress desiccation cracks encountered in landfill cover barriers. © 2008 Springer Science+Business Media B.V. 3 6
-
Geotechnical properties of soil-fiber mixture as a landfill cover barrier material 査読あり
Harianto T., Du Y., Hayashi S., Suetsugu D., Nanri Y.
Geotechnical Engineering 39 ( 3 ) 137 - 143 2008年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Geotechnical Engineering
In order to study the potential future uses of the landfill site for other applications (i.e. residential, park, etc.), some of the geotechnical properties need to be investigated when the landfill cover is used as a bearing layer during the post-closure period. The problem that could be encountered in the post-closure landfill is cracking due to the desiccation and differential settlement. An alternative solution to overcome this problem is the inclusion of polypropylene fibers (C H ) additives in the soil specimens. In this study, the investigation of the geotechnical properties such as compaction characteristics, unconfined compressive strength, tensile strength, and hydraulic conductivity were performed. It was found that the inclusion of fiber additive could improve the geotechnical properties of the soil specimens. The maximum dry density (γ ) of the soil-fiber mixtures increased. The compressive strength and ductility also significantly increased with the increase in the fiber content. Moreover, with the increase in the fiber content, the ductility in the post-peak region increased. The tensile strength of the soil-fiber mixture increased with the increase in the fiber content. The hydraulic conductivity tests showed that with the inclusion of fiber, the hydraulic conductivity of the soil-fiber mixtures change within acceptable levels. From the above tests, it has been concluded that fiber inclusion could significantly improve the geotechnical properties of landfill cover barrier material. The soil-fiber mixtures could be used as a landfill cover barrier material. 3 6 dmax
-
Appraisal of thermal properties of mud in the Ariake Sea, Japan 査読あり
Moqsud M., Hayashi S., Du Y., Suetsugu D.
American Journal of Environmental Sciences 4 ( 2 ) 129 - 135 2008年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：American Journal of Environmental Sciences
In order to explore the thermal properties of the Ariake Sea mud and to find out the affecting factors which affect these values, a portable thermal properties analyzer was used. Thermal conductivity, thermal resistivity, thermal diffusivity and volumetric heat capacity of the mud samples collected from both the tidal flat and inside the deep sea were measured in the laboratory. The thermal properties of mud collected from tidal flat showed a different trend from the mud collected from inside the sea due to the enough exposure to the sunlight and vigorous exchange of sea water in the tidal flat. Thermal conductivity of the Ariake mud was reduced 85-90% after it was oven dried and was increased up to 30% after the ignition loss test. Thermal resistivity of the Ariake mud increased dramatically after oven dried and it was less affected by the organic matter content. Thermal diffusivity was decreased 10-30% after oven dry however it increased up to 40% after the ignition loss test. The volumetric heat capacity of the Ariake mud was reduced up to 90% and increased 40% after the oven dry and ignition loss, respectively. © 2008 Science Publications.
-
Experimental investigation on strength and mechanical behavior of compacted soil-fiber mixtures 査読あり
Harianto T., Hayashi S., Du Y.J., Suetsugu D.
Geosynthetics in Civil and Environmental Engineering - Geosynthetics Asia 2008: Proceedings of the 4th Asian Regional Conference on Geosynthetics 392 - 397 2008年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Geosynthetics in Civil and Environmental Engineering - Geosynthetics Asia 2008: Proceedings of the 4th Asian Regional Conference on Geosynthetics
A series of laboratory tests has been carried out to investigate the using of C H (polypropylene) fiber as an additive to increase the strength of the compacted Akaboku soil. Fiber contents of 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, and 1.2% by weight were selected. The compaction test, unconfined compression test and tensile test were conducted in this study. In this study, fiber content was found as the main factor that affects the strength of the soil specimens. The results indicate that initially dry density increased with increased in fiber content up to 1.0% of fiber content and slightly decreased for fiber content of 1.2%. The similar trend also found in the compressive strength, tensile strength and also ductility of the soil specimens. The strength and ductility significantly increased with increasing the fiber content. 3 6
-
その他材料(3.地盤材料-リサイクル材料,<特集>第43回地盤工学研究発表会) 査読あり
末次 大輔
地盤工学会誌 56 ( 12 ) 2008年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：社団法人地盤工学会
-
Du Y., Hayashi S., Suetsugu D., Moqsud A.
Proceedings of the International Offshore and Polar Engineering Conference 558 - 563 2007年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Proceedings of the International Offshore and Polar Engineering Conference
In this paper, a series of laboratory infiltration tests were carried out to investigate the deterioration and natural remediation of the Ariake Sea tidal mud caused by the sea laver treatment practice and upward seawater seepage. The test results reveal that with the infiltration of the sea laver treatment agent in the tidal mud, mud sulfide content increased while pH decreased. The remediation test results indicate that with the infiltration of the fresh seawater, the sulfide content of the Iida site mud considerably reduced and pH value increased to an acceptable range for benthos living in the tidal flat mud. Copyright © 2007 by The International Society of Offshore and Polar Engineers(ISOPE).
-
Assessment of temperature profile in contaminated tidal flat in the Ariake Sea, Japan 査読あり
Moqsud M., Hayashi S., Du Y., Suetsugu D.
Proceedings of the International Offshore and Polar Engineering Conference 564 - 567 2007年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Proceedings of the International Offshore and Polar Engineering Conference
In order to get a clear idea about the thermal environment of the tidal flats of the Ariake Sea, two study areas, Iida and Higashiyoka tidal flats were selected. By installing five nos. of thermocouple at different specified depths (0.10 m,0.20 m,0.50 m,1.0 m and 2.0 m) connected with data logger (TDS-530) were used to observe diurnal variation of temperature during the 1 April to 8 April, 2006 at Higashiyoka tidal flat. The measured temperature was stored automatically at 1 h interval in the data logger. To observe seasonal variation of temperature in different depths , temperature was measured by inserting the thermocouple at 0.10 m depths interval in the last week of every month at both study areas in the Ariake sea tidal flat. The diurnal temperature variation was more visible near the surface (0.10 m and 0.20 m) indicating the influence of solar radiation in that portion, however in the deeper region (1.0 m and 2.0 m depth) the temperature was dominated by thermal properties of the mud. From seasonal variation of temperature it was seen that during spring and summer heat was transferred from subsurface to the deeper area but during winter and autumn opposite phenomenon was observed. Finally, equations are proposed to get the temperature profile in the tidal flat mud in different seasons. Copyright © 2007 by The International Society of Offshore and Polar Engineers(ISOPE). st th
-
An exploration of geoenvironmental condition of the Ariake Sea, Japan 査読あり
Moqsud M.A., Hayashi S., Du Y.J., Suetsugu D., Tanaka S., Shimoda Y.
Proceedings of the International Offshore and Polar Engineering Conference 568 - 571 2007年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Proceedings of the International Offshore and Polar Engineering Conference
Ariake Sea is famous for its various kinds of fisheries products and Porphyra sp. (sea weed) cultivations. But a dramatic decrease of catch of shells is observed for the last 3 decades in the Ariake Sea. The unfavorable geoenvironmental condition of the Ariake Sea is the most liable for this declination. In order to investigate the geoenvironmental condition of the Ariake Sea a regular monitoring was carried out both in the tidal flat area and inside the sea from 2002 to date. Some predetermined sampling points fixed by global positioning system (GPS), were selected for collecting the mud sample. The major geoenvironmental properties of the Ariake Sea mud such as sulphide content (SC), oxidation-reduction potential (ORP),pH, salinity were measured in different specified layers by using steel tube sampler (0.9 m long, 0.07 m diameter) regularly. The high sulphide content of the mud is found to be one of the most important causes for unfavorable geoenvironmental condition for the benthos in the Ariake Sea. A laboratory test was carried out by mixing the acid in different concentrations with mud and executed a survival test for Sinonovacula constricta and Ruditapes philippinarum shells. The deterioration of the mud quality was increased with increasing the concentration of the acid and no survival of both types of shells was observed after 10 days. The sulphide content seems to be decreasing annually but still it is above the favorable limit for the benthos living in the tidal flat mud. Copyright © 2007 by The International Society of Offshore and Polar Engineers(ISOPE).
-
Impacts of acid treatment practice on geoenvironmental conditions in the Ariake Sea, Japan 査読あり
Moqsud M., Hayashi S., Du Y., Suetsugu D.
Geotechnical Engineering 38 ( 2 ) 79 - 86 2007年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Geotechnical Engineering
The Ariake Sea is one of the best-known semi-closed shallow seas in Japan. The vast tidal flat of the Ariake Sea is famous for its abundant supply of shells, and a rich cultivation of Porphyra sp seaweed. In this study, the results of field tests as well as a series of laboratory tests are presented that demonstrate the impacts of acid treatment practice of cultivating Porphyra sp on the geoenvironmental conditions in the Ariake Sea. The salinity, pH, sulphide content (SC) and oxidation-reduction potential (ORP) of the Ariake tidal mud were measured in the samples collected from the tidal flat of the lida and Higashiyoka site. The ORP and sulphide contents of the lida mud is < 0 mV and > 0.5 × 10-3 kg/ kg dry-mud, respectively. All four parameters (salinity, pH, SC, ORP) were also measured in the laboratory under four different concentrations of acid. Another laboratory test was also conducted to observe the survival condition of the Sinonovacula constricta seashells at four different acid concentrations. Sinonovacula constricta seashells were unable to stay alive even for 7 days in the acid concentration of 0.11%. The results of both laboratory and field tests indicate a strong reduction condition in the mud due to acid treatment practice of the Porphyra sp which causes an imbalance of the marine eco-system. Consequently, there is a dramatic decrease of catch of seashells in the affected area of the Ariake Sea during the last 20 years.
-
ジオグリッドによる固化処理土の脆性的な引張抵抗特性の改善効果に関する実験的検討 査読あり
重久 伸一, 宮田 喜壽, 末次 大輔, 落合 英俊
土木学会論文集Ｃ 63 ( 2 ) 312 - 321 2007年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
本論文は，ジオグリッドによる固化処理土の脆性的な引張抵抗特性の改善効果について，室内試験の結果に基づき議論するものである．一連の実験では，固化処理土単体およびジオグリッドを配置した固化処理土に対し，三軸引張試験を圧密非排水条件で実施した．ジオグリッドを固化処理土に配置すると，破壊ひずみが固化処理土単体のときより大きくなること，クラックの連続的な発達を阻止できること，ジオグリッドと固化処理土の相互作用による引張抵抗の増加を見込めることを示す．そして，ジオグリッドによる引張抵抗の増加量は拘束圧によって変化しないという実験結果より，引張抵抗の増加量は見かけの粘着力としてモデル化できることを示す．
-
牛原 裕司, 林 重徳, 原 裕, 松尾 保成, 杜 延軍, 末次 大輔, MOQSUD M.Azizul
環境工学研究論文集 44 17 - 22 2007年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 土木学会
本研究では, 近年, 干潟底質の環境悪化が見られる有明海において, アゲマキ養殖の再生を目的とした底質改善を実施した. 底質改善材料には, 廃ガラスを原料として作られた発泡ガラス材と海砂を使用し, それぞれの改善効果を室内および現地試験により検証した.<BR>干潟底質の現状は, 夏季になるとバクテリアの活動により水産用水基準を超える硫化物が生成し, 底棲生物の棲息が困難な環境となっている. 本論文では, 発泡ガラス材や海砂を底質改善材料として底質に耕転・混合することで, 底質に含まれる有機物や硫化物の濃度が低下すること, さらに発泡ガラス材を使用することで台風・波浪による分級現象が緩和されることや, 間隙水の移動が促進されることを示した.
-
Suetsugu D., Mtyata Y.
5th ICEG Environmental Geotechnics: Opportunities, Challenges and Responsibilities for Environmental Geotechnics - Proceedings of the ISSMGE 5th Int. Congress II 1564 - 1569 2006年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：5th ICEG Environmental Geotechnics: Opportunities, Challenges and Responsibilities for Environmental Geotechnics - Proceedings of the ISSMGE 5th Int. Congress
This paper concerns geotechraical utilization of coal fly ash. A new consistency concept of coal fly ash is proposed to correspond to variety of its characteristics. And it is shown that strength properties are able to be evaluated by new consistency concept. In this study, six kinds of coal fly ash are applied to define consistency. Triaxial compression tests are carried out to investigate strength properties and to consider applicability of consistency concept for evaluating them. The summary of the results is shown as follows: (1) Coal fly ash-water mixtures are able to be classified into the flocked state, the viscoid state and the fluid state. The viscoid limit is defined as the boundary between the flocked and the viscoid state, and the fluid limit is defined as the boundary between the viscoid and the fluid state. (2) The optimam mixture ratio that shear strength appears the highest is founded. (3) The optimum mixture ratio is evaluated by a new index based on proposed consistency limits.
-
Annual and seasonal trends of sulphide content of tidal flat mud in the Ariake Sea, Japan 査読あり
Moqsud M., Hayashi S., Du Y., Suetsugu D.
Journal of Applied Sciences 6 ( 12 ) 2557 - 2564 2006年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Applied Sciences
The high Sulphide Content (SC) of mud is found to be one of the most important causes for unfavorable geo-environmental condition for the benthos in the acid contaminated Ariake Sea, Japan. In order to identify the temporal variation of the sulphide content of the mud, field tests were conducted in the lida and Higashiyoka tidal flat mud area of the Ariake Sea during the period 2002-2005. The collected column of mud was cut into a number of specific layers the thickness of which increased with increasing depth. The sulphide content of the mud in each layer was measured along with other physico-chemical properties. The sulphide content of the mud varies from 0.5 to 2.0×10 kg kg dry-mud, which is above the allowable limit (0.2×10 kg kg dry-mud) for the favorable condition of the benthos' life. In summer, the peak value of the sulphide content varies from 1.5 to 2.0×10 kg kg dry-mud since the bacterial activities increase with the elevated seasonal temperature. The peak value of the sulphide content, on the other hand, is relatively low (0.5-1.0×10 kg kg dry-mud) during the winter as the activities of bacteria as well as bioturbation decrease in the cold temperature. The maximum sulphide content depth was also influenced by the seasonal temperature. The highest sulphide content in the mud that decreases gradually from 2.0×10 kg kg dry-mud at 2002 to 1.3×10 kg kg dry-mud at 2005 indicates growing favorable conditions for the growth of benthos. © 2006 Asian Network for Scientific Information. -3 -1 -3 -1 -3 -1 -3 -1 -3 -1 -3 -1
-
有明海干潟を対象とした底質改善工法の検討 査読あり
牛原 裕司, 林 重徳, 松尾 保成, 田中 健太, 末次 大輔
低平地研究 ( 15 ) 31 - 36 2006年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：佐賀大学低平地防災研究センター
-
Moqsud M., Hayashi S., Du Y., Suetsugu D.
5th International Conference on Environmental Informatics, ISEIS 2006 2006年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：5th International Conference on Environmental Informatics, ISEIS 2006
The vast tidal flat mud of the Ariake Sea comprising almost 40% of the total tidal flat area of Japan is famous for its rich fishery products and sea laver cultivation. However, a dramatic decrease in the catch of the fishery products is observed in the tidal flat mud area over the last 20 years. The high sulphide content of the mud is found to be one of the most important causes for this unfavorable geo-environmental condition for the benthos. In order to identify the temporal variation of the sulphide content, pH, salinity and oxidation-reduction potential (ORP) of the mud, field tests were conducted in the Iida and Higashiyoka tidal flat mud area of the Ariake Sea during the period 2003-2005. The field tests consisted of the collection of the mud sample from 0 - 90 cm depth by inserting a steel pipe of length 90 cm and diameter 7 cm into the tidal mud. The collected column of mud was cut into a number of specific layers the thickness of which increased with increasing depth. The sulphide content, pH, salinity and oxidation-reduction potential (ORP) of the mud in each layer were measured along with other physico-chemical properties. The sulphide content of the mud varies from 0.5 to 2.0 mg/g dry-mud, which is above the allowable limit (0.2 mg/g) for the favorable condition of the benthos' life. In summer (August - September), the peak value of the sulphide content varies from 1.5 to 2.0 mg/g since the bacterial activities increase with the elevated seasonal temperature. The peak value of the sulphide content, on the other hand, is relatively low (0.5 -1.0 mg/g) during the winter (December - February). The highest sulphide content in the mud that decreases gradually from 2.0 mg/g at 2002 to 1.3 mg/g at 2005 indicates growing favorable conditions for the growth of benthos. The pH value, salinity and oxidation reduction potential value are also noticeably changed during the summer and the winter temperature in the tidal flat mud during the year 2003-2005.
-
Shear resistance and deformation characteristics of sedimented coal fly ash-cement mixture 査読あり
Suetsugu D., Kogure K., Miyata Y., Ochiai H.
Zairyo/Journal of the Society of Materials Science, Japan 51 ( 1 ) 8 - 12 2002年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Zairyo/Journal of the Society of Materials Science, Japan
It is necessary to utilize coal fly ash in geotechnical engineering field. Coal fly ash is a useful material. In case of using as reclamation material, cement is mixed into coal fly ash to stabilize the ground before reclaiming coal fly ash. Effects of cementation on mechanical properties of coal fly ash should be investigated. Authors focus to utilize coal fly ash as reclamation material in the coastal area. In order to investigate effects of cementation on mechanical properties of sedimented coal fly ash, triaxial compression tests were carried out. From a series of triaxial test results and considerations, the following conclusions were obtained: (1) Coal fly ash sedimented in losser condition with increasing amount of cement. (2) The increase of shear resistance caused by cementation effects appeared in small strain and low confining stress level. (3) Dilatancy property of sedimented coal fly ash - cement mixture depended on confining stress and cementation.
DOI： 10.2472/jsms.51.8
-
Experimental consideration in mechanical property of accumulated coal fly ash 査読あり
Suetsugu D., Miyata Y., Kogure K.
Proceedings of the International Offshore and Polar Engineering Conference 4 140 - 145 2001年
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Proceedings of the International Offshore and Polar Engineering Conference
It is necessary to utilize coal fly ash in the coastal engineering field. Coal fly ash is a self-hardening material. In case of using as reclamation material, effects of self-hardening characteristic on mechanical properties should be investigated. Authors focus to utilize coal fly ash as reclamation material in the coastal area. In this paper, in order to investigate effects of self-hardening characteristic on mechanical properties of accumulated coal fly ash triaxial compression tests were carried out. From a series of triaxial test results and considerations, the following conclusions were obtained: (1) The increase of shear resistance caused by self-hardening characteristic appeared in small strain and confining stress region, and it reduced with progressing shear deformation. (2) Dilatancy property of coal fly ash depends on confining stress, and extent of self-hardening characteristic. (3) Effect of self-hardening characteristic should be considered in evaluating deformation and shear resistance.