著者

澤田 麻美 小林 昭男 宇多 高明 三浦 正寛

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.21, pp.457-462, 2005 (Released:2011-06-27)

参考文献数

1

被引用文献数

1 2

---

Beach changes of the Akiya coast located on the western shore of Miura Peninsula were investigated. Comparison of aerial photographs and analysis of shoreline changes were carried out. It was found that sand movement to wave shadow zone of the fishing port is the main cause of the beach erosion of this coast, as well as decrease in fluvial sand supply from the rivers. Erosion rate was determined from the difference of the colors attached to the seawall.

著者

関口 浩二 遠山 哲次郎 荒田 崇 清水 敏晶

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.13, pp.853-858, 1997 (Released:2011-06-27)

参考文献数

4

被引用文献数

1

---

Lake Saroma is an inland sea-lake on the Sea of Okhotsk. As the lake's environment is suitable for aquiculture, it is widely used for natural sea farming.Ice floes usually reach Okhotsk Sea coast of Hokkaido from late January through early February. When ice floes arrived before Lake Saroma had sufficiently frozen up, the inflow of ice into the lake damaged aquiculture facilities. As a countermeasure for this, construction of ice booms to control ice floes began in 1994 and 10 spans out of 13 planned have since been completed.In this study, the effectiveness of ice booms in controlling ice floes in an actual sea area is confirmed, factoes concerning the tension of the main wire, an important point in design, are analyzed using research results, and the design and actual values are compared.

著者

大川 豊 矢後 清和 太田 真 山田 義則 高野 宰 関田 欣治

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.20, pp.1217-1222, 2004 (Released:2011-06-27)

参考文献数

10

被引用文献数

1 1

---

This paper describes the technical feasibility study and the economical evaluation of the floating wind power system. The box-girder type floating structure installed three wind turbines is proposed as a concept. The 5MW class propeller type turbines are adopted. The box girder with simple structures is favorable in the cost performance. Moreover, the wave induced motion and the righting moment can be optimized easily. The estimations of the static inclination and the wave induced motion were carried out in technical study. The relations between wind loads and motions or inclinations were investigated by the wind tunnel test. On the numerical analysis of motions, the fluid dynamic forces were calculated using the potential theory with zero draft assumption in the estimation of motion. The floating structure model was consisted by beam elements of FEM. The calculation result showed that the motion and the inclination in an operation condition are less than 5 degrees. According to the economic estimation, it was presumed that the proposed concept can be attained to the equally cost of water-power generation and others.

著者

清水 隆夫 玉田 正男

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.20, pp.617-622, 2004 (Released:2011-06-27)

参考文献数

5

被引用文献数

8 8

---

The density of uranium in the seawater is only 3 mg/m3, but its total amount is 4.5 billion tons. In the last report, the braid type adsorbent was proposed with its mooring system for the collection of the uranium from the sea. And, it was shown that a high performance of the adsorbent and a big fall in weight of the mooring system are feasible and there's no problem of the adhered creature. In this report, it is shown that 134 km2 of mooring basin is needed for annual product of 1200 tons of uranium. In addition, 6000 km2 and over of suitable basin for the collection of the uranium is shown between Okinawa Islands and Tosa Bay.

著者

星上 幸良 小林 昭男 宇多 高明 三浦 正寛 熊田 貴之 三波 俊郎

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.19, pp.481-486, 2003 (Released:2011-06-27)

参考文献数

9

被引用文献数

1

---

Preventive method of beach erosion and accretion triggered by the formation of wave shadow zone associated with extension of port breakwater is investigated through the field observation, taking the Shimohara fishing port in Tateyama City in Chiba Prefecture as the example. This phenomenon is well-known in coastal engineering, but in Japan this kind of beach erosion and accretion have been repeatedly reported. In order to solve this problem, not only the research in engineering method, but also improvement of the environmental assessment system are required so as to include the prediction of topographic changes in the items of environment assessment.

著者

中瀬 浩太 林 英子

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.18, pp.31-36, 2002 (Released:2011-06-27)

参考文献数

4

被引用文献数

1 1

---

Tokyo Port Wild Bird Park, which was originally a part of the reclaimed industrial area, was constructed in 1989 by the request of the local citizens. Since then, the seaside park that includes an artificial lagoon has provided precious opportunities of natural experience for the people in urbanized Tokyo-Bay Area.For the maintenance and management of the park, volunteer citizens groups have played a crucial role. Since the opening of the park, the highly motivated volunteer groups, in cooperation with members of Wild Bird Society of Japan, have continuously monitored the topographical change of the artificial lagoon and the situation of birds, benthos, and vegetation. In addition, the volunteer groups carriedout some field experiments. For example, they constructed an artificial creek and monitored the growth of thereed around it. They also constructed bamboo fences to check their anti-erosion effect at the shoreline and seabed. These continuous activities help to build better understanding of the environmental management in an artificial lagoon. The authors suggest the need of the involvement of more persons with biological knowledge, in addition to the volunteer group, in order to enhance the quality of the management method.

著者

松浦 邦明 鈴木 史朗 橋本 典明 本橋 昌志

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.22, pp.85-90, 2006

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We develop a real-time wave information and analysis system on the basis of a data assimilation technique, the optimum interpolation method, applied for wave observation data and forecasted data. The system can provide nowcast wave information for the sea area where there is no wave observation point. In the system, first, the initial estimate (nowcast) is computed in real-time with the observation data and forecasted information, and then the estimate is corrected after 12 hours with more accurate forecasted wave information. Finally, the corrected data is stored in the wave information database for analysis. We investigate the characteristics of the nowcast wave data and confirmed that the accuracy of the data is high enough for practical applications.

著者

山崎 宗広 上嶋 英機 村上 和男

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.20, pp.977-982, 2004 (Released:2011-06-27)

参考文献数

2

---

Amagasaki Harbor is enclosed coastal sea. Therefore water in a harbor basin is stagnant, and the water quality is deteriorated. In this study, we carried out hydraulic model experiments in order to enhance the water exchange of Amagasaki Harbor. The channel making technique is very effective to strengthen the flow in Amagasaki Harbor. This is because a Yodo River flows into harbour basin. And it is also highly effective to enhance water exchange of the harbor water.

著者

前田 幸男 永尾 浩一 牛嶋 龍一郎 春日井 康夫 菅野 高弘 中澤 博志

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.24, pp.285-290, 2008 (Released:2010-08-25)

参考文献数

8

---

It is known that “Blast Densification Method” is a technique which can improve the ground strength for the liquefaction by the artificial trembling with the shock wave of explosives detonation set in ground. It is carried out a full scale test which has the airport facility at Ishikari Bay New Port in Hokkaido Island, Japan.The shaking by blasting continues for about two minutes, with 1769kg explosives, 583 delay numbers, at about 1.6 hectares experiments. It is executed safely, surely without damage to structures by blasting.As a result of the experiment, it is confirmed the increasing excess pore water pressure, sand pumping phenomenon, and settlements after basting. This report is described a summary of experiment on this test

著者

堀田 新太郎 カール ノードストローム

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.20, pp.479-484, 2004 (Released:2011-06-27)

参考文献数

37

---

Beach nourishment is now the principal option for shore protection in some countries, such as the USA and The Netherlands, and it is being increasingly employed in other countries, particularly in Western Europe. Few studies have evaluated the biological aspects, especially the benefits that result from the widened beach. This paper summarizes the state of the art on biological implications of beach nourishment operations in the USA to identify the biological tradeoffs involved in these operations and steps that should be taken to maximize beneficial uses of beach fill.

著者

長野 章 佐藤 信一 川瀬 将

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.7, pp.265-270, 1991 (Released:2010-03-17)

参考文献数

2

---

The objective of this study is lay the island type offshore fishing ports plan. This developmentplans of fishing ports (Kutuo fishing port and Mitikawa fishing port) which is adaptableto drift sand, is able to accommodate fishing boats safety, and causes least effectsagainst topographic change.

著者

市原 正史 前田 武 石原 弘一 岩崎 峯夫 秋園 純一 根本 孝志 朝倉 修

出版者

公益社団法人 土木学会

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.6, pp.359-364, 1990 (Released:2010-03-17)

参考文献数

9

著者

安田 誠宏 間瀬 肇 小西 秀誉 松下 紘資 徳永 誠之

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.24, pp.519-524, 2008 (Released:2010-08-25)

参考文献数

6

被引用文献数

6 6

---

A set of experiments was conducted to examine the stability of new type of wave dissipating blocks. It was confirmed from the experimental results that offshore wave steepness influences the stability of blocks. The parameters of stability number formula were derived with classification of wave steepness. Required weight of new block against a design wave can be reduced to 90 percent compared to a typical standard block because the stability is being improved. The wave steepness relates deeply to the breaker type, and wave steepness' effect should not be neglected in the stability estimation of blocks. In order to separate the effects of wave steepness and wave breaking, it had better to conduct the experiments with flat bottom condition for further investigation of blocks' stability.

著者

高橋 重雄 酒井 洋一 森屋 陽一 内山 一郎 遠藤 仁彦 有川 太郎

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.24, pp.159-164, 2008 (Released:2010-08-25)

参考文献数

27

---

The primary objective of tsunami disaster mitigation is to reduce the casualties. The major cause of the deaths is drowning by tsunami current, especially during evacuation. In the paper, the causes of deaths are discussed through reference to past experiences. A fault tree is presented to summarize the physical danger posed by tsunami waves to the human body, and the personal danger is discussed based on the tree. The stability of the human body against wave front collision and tsunami currents is discussed and threshold conditions are proposed. The time for evacuation is usually very limited and the risk of encountering a tsunami during evacuation is often high. Walking in inundated areas during a tsunami attack is especially dangerous. Vertical evacuation is highly recommended.

著者

村木 義男 竹内 政夫 佐伯 浩

出版者

公益社団法人 土木学会

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.6, pp.149-154, 1990 (Released:2010-03-17)

参考文献数

4

著者

遠藤 仁彦 早川 哲也 笹島 隆彦 金川 均

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.11, pp.175-180, 1995 (Released:2010-03-17)

参考文献数

1

著者

平石 哲也 長谷川 準三 黒木 啓司

出版者

公益社団法人 土木学会

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

no.14, pp.275-279, 1998

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Long period waves often cause large surging motion of moored vessels by resonance to naturaloscillation of the mooring system composed of the elastic hawsers and ship body. In order to preventthe amplification of long period waves in harbor by the reflection, the wave absorbing beach isproposed. The artificial beach with mild slope can reduce the reflection coefficient. The appropriateinstallation planning for beaches in harbor is discussed on basis of the results of numericalsimulation.

著者

松原 雄平 野田 英明 依藤 正典 中谷 英明

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.13, pp.693-698, 1997 (Released:2011-06-27)

参考文献数

8

---

Nakaumi lake is shallow with extensive intertidal sand and mud flats. The eelgrass (Zoesta marina) zone in the lake may function as an important refugee for many resident and transient species, especially where other structural habitats are poor. In this paper, a new method for eelgrass bed creation is introduced and discussed Field observations have been carried out and suitability conditions of eelgrass are evaluated by field data.

著者

柳生 忠彦 白石 修章 八尋 明彦 豊島 照雄

出版者

公益社団法人 土木学会

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.5, pp.197-201, 1989 (Released:2010-03-17)

著者

山本 吉道 ウィブール ウッチャン 飯田 邦彦 河合 恭平

出版者

Japan Society of Civil Engineers

雑誌

海洋開発論文集 (ISSN:09127348)

巻号頁・発行日

vol.23, pp.81-86, 2007

被引用文献数

1

---

We tried to devise a method for estimating the degree and geographic extent of tsunami damage using satellite photographs in two case studies of damage to Thailand's west coast due to the Indian Ocean tsunami. Following results were obtained from those case studies: the extent of a flood area can be generally estimated from discoloration of vegetation zone assuming such vegetation originally existed along the coast; house damage could be estimate by deciphering whether each roof was lost or not, however if the roof remained, the degree of damage to walls and pillars could not be discerned.<BR>Therefore, we develop a method to get marginal thickness of walls and marginal width of pillars which break on arbitrary positions using a distribution of tsunami heights on a coastline and a distribution of ground heights. In addition, the extent of a flood area can be presumed if there are the above-mentioned distribution data and elapsed data of sea water levels at the time of a tsunami invasion.