| JaLCDOI | 10.18926/fest/11503 |
|---|---|
| フルテキストURL | 008_053_062.pdf |
| 著者 | A.M. Dewan| 西垣 誠| 小松 満| |
| 抄録 | Flood becomes regular feature in riverrine Bangladesh. Every year, around 21 percent of land is flooded during monsoon season, however, in severe situation this figure shot up to more than 60 percent of total land. This paper is an attempt to analyze hydrological characteristics of two catastrophic events (1988 and 1998 flood) in the light of flood history in Bangladesh. The analysis demonstrates that the 1998 flood was more severe than the 1988 one. Moreover, the 1998 flood was also prolonged than the 1988 flood due to heavy rainfall inside and outside of the country. Finally, flood management issues in Bangladesh have been analyzed and found that structural solution to mitigate flood is not the only solution. Based on the analysis some possible mitigation options are put foward. |
| キーワード | Flood Flood Management Danger level Peak floods Deforestation |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2003-03 |
| 巻 | 8巻 |
| 号 | 1号 |
| 開始ページ | 53 |
| 終了ページ | 62 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313768 |
| JaLCDOI | 10.18926/fest/11577 |
|---|---|
| フルテキストURL | 005_107_112.pdf |
| 著者 | Tohari Adrin| 西垣 誠| 小松 満| |
| 抄録 | Failures of railway embankments in Japan usually occur during rainfall period due to the rise of water level in the embankments. Laboratory experiments were carried out to elucidate the initiation of failure of embankment under the rise of water level. The changes in pore-water pressure were monitored during the rise of water table and at the initiation of failures. The experiment results showed that main failure of embankment was initiated by development of localized unstable area at the toe of the embankment models during the rise of water level. This indicates that failure of embankments was a consequence of instability of the toe of the slope induced by saturation process under drained condition. |
| キーワード | embankment failure process seepage face toe failure overall instability |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2000-02-29 |
| 巻 | 5巻 |
| 号 | 1号 |
| 開始ページ | 107 |
| 終了ページ | 112 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313411 |
| JaLCDOI | 10.18926/fest/15045 |
|---|---|
| フルテキストURL | 014_023_028.pdf |
| 著者 | Chegbeleh Larry Pax| 西垣 誠| Akudago John Apambilla| Alim Md. Abdul| 小松 満| |
| 抄録 | During underground space development, groundwater seepage mostly occurs which may seriously affect the stability of deep excavations as well as retard progress of construction. For smooth progress of work, effective construction and operation of a disposal facility for high level radioactive waste (HLW), it is important to control seepage into excavations by sealing off fractures or fissures and excavation disturbed zones (EDZ) to control groundwater inflow during the construction phase of such a facility. In this study, a series of experiments were conducted on ethanol/bentonite slurries in the laboratory with the aim of determining the effect of a hydrophilic solvent such as ethanol on the hydraulic and injection characteristic of bentonite slurry for the sealing of fissures to control ground water seepage during the construction phase of a repository. Preliminary results revealed ethanol/bentonite slurry as an effective grouting material capable of penetrating micro fractures (100μm or less) and with the permeability of the grouted medium being as low as 10E-7cm/s. The results also show that the effectiveness and efficiency of grouting is dependent on the type of injection and fissure size. Dynamic injection was observed to be efficient as it was able to inject high dense slurry. |
| キーワード | Dynamic injection permeability swelling bentonite clay |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2009-03-16 |
| 巻 | 14巻 |
| 号 | 1号 |
| 開始ページ | 23 |
| 終了ページ | 28 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002307422 |
| JaLCDOI | 10.18926/fest/11431 |
|---|---|
| フルテキストURL | 011_051_055.pdf |
| 著者 | 西垣 誠| 小松 満| Akudago John Apambilla| Shinshi Yoshihide| Kawakami Kenji| Kumamaru Koji| |
| 抄録 | A laboratory validation of a proposed new method of determining the in-situ effective porosity of unsaturated soils was carried out on unsaturated river sand. The proposed method consists of boring a small diameter hole into the soil and inserting an Amplitude Domain Reflectometry (ADR) probe at the bottom part of the hole. Water is supplied into the hole till saturation and later de-saturated. The water content with time is determined from the ADR probe voltage potential readings. The effective porosity is determined from the difference between the saturated and de-saturated water contents. However, in the laboratory, the water is supplied through the top and bottom parts of the sample. From the experiments the obtained effective porosity ranged from 0.28 to 0.29 for wetting from the top with an average of 0.287 and 0.29 to 0.30 for wetting from the bottom with an average of 0.293. The determined effective porosity ranged from 71.7-73.3% of the real initial porosity of 0.40 of the river sand. The maximum attained degree of saturation during the experiment was 91%. The results indicated that the method will be suitable and useful in determining the effective porosity of medium grained unsaturated soils. |
| キーワード | Underground dam Effective porosity Storage capacity Freshwater development |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2006-03-15 |
| 巻 | 11巻 |
| 号 | 1号 |
| 開始ページ | 51 |
| 終了ページ | 55 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313335 |
| フルテキストURL | fulltext.pdf |
|---|---|
| 著者 | Fujita, Claudia| Akhtar, M. Shahbaz| Hidaka, Ray| Nishigaki, Makoto| |
| キーワード | Dissolved iron removal Chemical clogging Open-loop geothermal systems Retention potential Wooden charcoal |
| 発行日 | 2022-02-07 |
| 出版物タイトル | Applied Water Science |
| 巻 | 12巻 |
| 号 | 3号 |
| 出版者 | SPRINGER HEIDELBERG |
| 開始ページ | 30 |
| ISSN | 2190-5487 |
| 資料タイプ | 学術雑誌論文 |
| 言語 | 英語 |
| OAI-PMH Set | 岡山大学 |
| 著作権者 | © The Author(s) 2022 |
| 論文のバージョン | publisher |
| DOI | 10.1007/s13201-022-01574-x |
| Web of Science KeyUT | 000752014000004 |
| 関連URL | isVersionOf https://doi.org/10.1007/s13201-022-01574-x |
| JaLCDOI | 10.18926/15440 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_28_1_71.pdf |
| 著者 | 西垣 誠| Sudinda Teddy| Hishiya Tomoyuki| 河野 伊一郎| |
| 抄録 | In this paper, method of Eulerian Lagrangian numerical analysis is used to described Advection-Dispersion phenomena. The influence of concentration to the density of fluid is considered. A laboratory model of a two dimensional confined aquifer containing an isotropic, homogeneous porous medium (Hosokawa et.al 1989) was used to validate the applicability of Advection-Dispersion of numerical analysis with steady and unsteady state condition [1]. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 1993-11-30 |
| 巻 | 28巻 |
| 号 | 1号 |
| 開始ページ | 71 |
| 終了ページ | 85 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002307975 |
| JaLCDOI | 10.18926/15492 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_25_1_59.pdf |
| 著者 | 河野 伊一郎| 西垣 誠| Okada Junji| |
| 抄録 | In this paper, we propose a method to determine the coefficients of permeability of the unconfined aquifer consisted of two different permeability layers. With mixing the conventional pumping test and falling head permeability test, the coefficients of permeabilitiy k(1) and k(2) were obtained. The validity of the proposed method is investigated by using the numerical simulation. As the results, it becomes apparent that the proposed method is applicable to real hydarulic problems. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 1990-12-14 |
| 巻 | 25巻 |
| 号 | 1号 |
| 開始ページ | 59 |
| 終了ページ | 69 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002307472 |
| JaLCDOI | 10.18926/fest/11501 |
|---|---|
| フルテキストURL | 010_075_081.pdf |
| 著者 | Kankam-Yeboah Kwabena| Asare Enoch B.| Gyau-Boakye Philip| 西垣 誠| |
| 抄録 | The rapid impact assessment (RIAM), which was developed in Denmark, is a new tool for the execution of environmental impact assessments. RIAM is quite flexible, transparent and leaves a permanent record, which can be independently checked, validated or updated. RIAM has successfully been used to prioritize water resources management problems in Ghana in the order of which problems call for the most urgent attention. The priority list was easily validated and accepted to be the true reflection of the situation at a national workshop in which experts and representatives from water agencies, donor agencies, university faculties and departments, research institutes, private institutions and organizations including Non Governmental Organizations (NGOs) participated. The study has shown that RIAM, which can also be used in a developing country like Ghana, is a very useful tool in such prioritization process as has been applied in this exercise. |
| キーワード | Water resources management problems prioritization impact indicators RIAM river basins Ghana |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 75 |
| 終了ページ | 81 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313917 |
| JaLCDOI | 10.18926/fest/11496 |
|---|---|
| フルテキストURL | 010_057_065.pdf |
| 著者 | Dewan Ashraf M.| Alam Md. Mahabubul| 西垣 誠| |
| 抄録 | This paper is an attempt to develop a series of maps that precisely depict flood prone areas in Greater Dhaka, Bangladesh using remote sensing techniques. Multi-temporal RADARSAT SAR data were acquired and employed to delineate open water flood boundary during the floods of 1998 and 2000. Using a threshold algorithm, SAR data is segregated into water and non-water areas. The empirical threshold value was obtained by using visual interpretation technique, local knowledge of the study site and by deriving corresponding pixel values to land/water from each image. The result demonstrated that 53 percent of the study area was heavily inundated in 1998 flood which is the largest submerged area during a catastrophic scenario. In contrast, 35.32 percent area was flooded during the year 2000 which represents the area under water for a normal event. Using the reference data acquired from field visit, derived flood maps were further validated. Moderate accuracy is obtained for all flood maps, however, July 1998 image attained the highest overall accuracy (86%) in the dataset. The derived flood maps are expected to be useful to mitigate losses of lives and property from river water flooding in Greater Dhaka. Furthermore, this information would be worthwhile to develop an efficient flood disaster management system. |
| キーワード | SAR open water flood 1998 and 2000 floods Greater Dhaka RADARSAT |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 57 |
| 終了ページ | 65 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313953 |
| JaLCDOI | 10.18926/fest/12829 |
|---|---|
| フルテキストURL | 13_063_066.pdf |
| 著者 | Akudago Apambilla John| 西垣 誠| Chegbeleh Larry Pax| Alim Md. Abdul| 小松 満| 熊丸 耕志| |
| 抄録 | Filters are essential in the design of embankments/dams, drains and wells for water and oil supplies. As a result of these functions, filter use is increasing. In order to use the required filter, various empirical relations have been given based on mathematical and field experience. However, these guidelines have not worked to perfection considering the fact that clogging within the filter face is a serious challenge. A short review on filter design criteria is given in this script coupled with a numerical formulation to propose the design limits. |
| キーワード | filter particle clogging filter classification numerical model equation force of attraction |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2008-03 |
| 巻 | 13巻 |
| 号 | 1号 |
| 開始ページ | 63 |
| 終了ページ | 66 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002304909 |
| JaLCDOI | 10.18926/fest/11531 |
|---|---|
| フルテキストURL | 006_047_052.pdf |
| 著者 | 小松 満| 西垣 誠| |
| 抄録 | For evaluating subsurface contamination, sampling method (boring) is commonly used, but this method cannot monitor the change of in-situ contamination and concentration with respect to time. The purpose of this study is to develop a measuring system for subsurface contamination in which a so-called FDR-V system (Frequency Domain Reflectometry with Vector network analyzer) was employed to measure the salinity contaminant. This FDR-V method is a coaxial probe method,which allows the measurement of the complex dielectric constant from 1GHz to 18GHz. The experimental study indicates the possibility in measuring both the salinity concentration and volumetric moisture content. |
| キーワード | Dielectric constant Subsurface Salinity concentration Volumetric moisture content |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2001-02-28 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 47 |
| 終了ページ | 52 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313354 |
| JaLCDOI | 10.18926/fest/11502 |
|---|---|
| フルテキストURL | 010_083_088.pdf |
| 著者 | Kankam-Yeboah Kwabena| Darko Philip K.| 西垣 誠| |
| 抄録 | Groundwater has been recognised as the most cost-effective option of safe water supply to rural communities in Ghana. The demand for potable water has led to the drilling of a large number of boreholes in many parts of the country. To establish the threshold of groundwater development from storage in a major river catchment (Pra River) in South-West Ghana, studies on recharge to the weathered aquifer and statistical evaluations of specific capacity and potential yield have been carried out. The SACSMA conceptual hydrological modelling system was used for the recharge estimate. With recharge rate of 50 mm/yr, the natural groundwater resources in the basin was estimated to support a maximum withdrawal of 12 l/s for a 10 hour per day pumping. The groundwater resources potential of 1.6 l/sｋ㎡ could be considered the threshold of groundwater exploitation in similar river basins in South-West Ghana. A study into the relation between permeability and recharge under different conditions and scenarios is required to define their limiting role in groundwater resources development. |
| キーワード | Groundwater storage recharge aquifer specific capacity base flow hydrologic budget |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 83 |
| 終了ページ | 88 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313829 |
| JaLCDOI | 10.18926/fest/11500 |
|---|---|
| フルテキストURL | 008_039_052.pdf |
| 著者 | Kankam-Yeboah Kwabena| Dapaah-Siakwan Stephen| 西垣 誠| 小松 満| |
| 抄録 | Increasing human population, changing lifestyles and environmental considerations have resulted in increased utilization of groundwater resources worldwide. Thus, in turn, has led to the decline of groundwater levels in some countries and Ghana is no exception to this problem. To augment the availability of groundwater resources for various uses, numerous techniques have been developed in many part of the world, one of which is the construction of underground dams. The successful construction and utilization of underground dams, however, depends very much on the physical and hydrogeological conditions at the dam sites. Ghana is underlain by Precambrian crystalline igneous and metamorphic rocks ; and Paleozoic consolidated sedimentary formations. There are further subdivided and described locally as the Birimian, Dahomeyan, Buem, Togo Series, Tarkwaian, Granites, Voltain, Coastal Block Fault, Coastal Plain and Quaternary Alluvium. The review of these and the pre-requisite conditions necessary for the construction of underground dams indicate that underground dams could be constructed and utilized in some parts of Ghana, especially where the overburden is shallow, in the Dahomeyan granites and in the recent formations consisting of alluvial and coastal sands and gravels. This paper is part of a continuing research programme being carried out by the authors. |
| キーワード | hydrogeology geology underground dam sand-storage dam sub-surface dam water supply |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2003-03 |
| 巻 | 8巻 |
| 号 | 1号 |
| 開始ページ | 39 |
| 終了ページ | 52 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313713 |
| JaLCDOI | 10.18926/15744 |
|---|---|
| フルテキストURL | Mem_Sch_Eng_OU_14_1_95.pdf |
| 著者 | Nishigaki Makoto| Kono Iichiro| |
| 抄録 | In order to apply the numerical method to practical groundwater flow problem in the field, the hydraulic properties must be estimated. In this paper, new methods of analyzing drawdown tests were developed and illustrated with some examples to determine hydraulic properties of aquifer. Drawdown tests sometimes have to be performed near the boundary of the aquifer or in the much groundwater supplied aquifer. In such instances, the assumption that the aquifer is of infinite areal extent is no longer valid. Therefore the analytical solutions of unsteady flow due to drawdown test are derived in the conception of "Island Model" that the shape of groundwater level is fixed by the circular water supply which is equilibrium with the pumping rate. By using these solutions, new methods of analyzing drawdown tests which are performed in a confined aquifer and an unconfined aquifer were given respectively and the effect of influence region was evaluated. The example analysis to determine permeability and storage coefficient were shown. As the results,the propriety of the solutions is verified comparing the analytical results with the drawdown test data taken from a real aquifer project. |
| 出版物タイトル | Memoirs of the School of Engineering, Okayama University |
| 発行日 | 1979-12-01 |
| 巻 | 14巻 |
| 号 | 1号 |
| 開始ページ | 95 |
| 終了ページ | 126 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002307822 |
| JaLCDOI | 10.18926/fest/11464 |
|---|---|
| フルテキストURL | 009_087_098.pdf |
| 著者 | Kankam-Yeboah Kwabena| Gyau-Boakye Philip| 西垣 誠| 小松 満| |
| 抄録 | Three principal river basins are found in Ghana and the Volta River Basin is the major one, covering about three -quarters of Ghana. The basin is shared with Mali, Burkina Faso, Cote d'Ivoire, Togo and Benin. Water from the Volta River Basin is used for drinking water supply, generating hydro-electric power, irrigation, inland fisheries and lake transport. The sustainable management of the Volta River Basin is thus of great importance. Land use activities in the basin are thus closely monitored not only in Ghana, but also in the other riparian countries as well. This paper presents information and data on the water resources and environmental management of the Volta River Basin in Ghana. |
| キーワード | water resources environmental management Volta River Basin Ghana water utilization |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2004-02-27 |
| 巻 | 9巻 |
| 号 | 1号 |
| 開始ページ | 87 |
| 終了ページ | 98 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313917 |
| JaLCDOI | 10.18926/ESR/47747 |
|---|---|
| タイトル（別表記） | Newly proposed landform division in the Kibi Plateau area: Application for a hazard map of landslides |
| フルテキストURL | esr_018_1_005_010.pdf |
| 著者 | 鈴木 茂之| 大溝 佑奈| 平田 稔| 西垣 誠| |
| 抄録 | The Kibi Plateau is characterized by horizontal skylines and they are considered to be an uplifted peneplain. Landform of the plateaus in central part of Okayama Prefecture is divided into "Kibi plateau landform" and "Recent dissecting landform". The Kibi plateau landform is composed of low relief surface and relict mountain. The altitude of the low relief surface varies from 300 to 450m in Kayo area, and 200 to 350m in Kanayama area. The Recent dissecting landform is characterized by escarpment and cuts the Kibi plateau landform. Knick-point is formed at the boundary between two landforms and steep slope is distributed just below the knick-point. The steep slope of the recent dissecting landform is unstable and a potential of landslide is high. |
| キーワード | Kibi Plateau landslide knick-point Okayama Prefecture |
| 出版物タイトル | Okayama University Earth Science Report |
| 発行日 | 2011-12-26 |
| 巻 | 18巻 |
| 号 | 1号 |
| 開始ページ | 5 |
| 終了ページ | 10 |
| ISSN | 1340-7414 |
| 言語 | 日本語 |
| 著作権者 | © 2011 by Okayama University Earth Science Reports Editorial Committee All Rights Reserved |
| 論文のバージョン | publisher |
| NAID | 120003796475 |
| 著者 | 西垣 誠| 小松 満| 金 萬鎰| |
|---|---|
| 発行日 | 2003-08 |
| 出版物タイトル | 環境制御 |
| 巻 | 25巻 |
| 資料タイプ | 紀要論文 |
| JaLCDOI | 10.18926/fest/11600 |
|---|---|
| タイトル（別表記） | Research on Prevention of Groundwater Flow Blockage by the Detour Permeation Method |
| フルテキストURL | 002_033_050.pdf |
| 著者 | 佐藤 常雄| 西垣 誠| |
| 抄録 | With the increase of underground construction in metropolitan areas in recent years, the problem of associated earth retaining works cutting off the natural flow of groundwater has increased in both scale and extent. The authors are proposing a new diaphragm wall method that does not inhibit the flow of groundwater. This paper describes the verification of the detour permeation achieved by the new diaphragm wall method and the experimental results related to the blockage of this groundwater flow. |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 1997-01-10 |
| 巻 | 2巻 |
| 号 | 1号 |
| 開始ページ | 33 |
| 終了ページ | 50 |
| ISSN | 1341-9099 |
| 言語 | 日本語 |
| 論文のバージョン | publisher |
| NAID | 120002313670 |