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

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
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

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

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.
著者
山本 吉道 河合 恭平 高野 哲男
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.24, pp.1339-1344, 2008

In this research, the Ishikawa-ken area of Kaetsu coastal zone and Enshu-nada coastal zone are selected as the coastal zone where a large-scale sandy beach is left, and sedimentation control of those zones is examined in order to recover the continuity of overall movement of earth and sand, and the following plans are proposed:<BR>1) An efficient countermeasure based on sand recycling by shipping and natural carrying system due to waves and currents in the Ishikawa-ken area of Kaetsu coastal zone.<BR>2) An effective countermeasure based on natural carrying power due to Tenryu river flow and a sand bypass by trucking for short distance in Enshu-nada coastal zone.
著者
山本 吉道 中山 正広 岩井 健浩
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
no.21, pp.39-44, 2005
被引用文献数
1

The great earthquake of M9 was generated in the North Sumatra offing at 7: 58 on December 26th, 2004, and the serious tsunami calamity was produced in every coast of Indian Ocean. We report on the damage survey that we carried out from January 9th to 12th in Thai western coast where typical tsunami damage was produced.<BR>(1) The tsunami height of Khoa Lak coast was about 9m on the sea level, and almost all walls and pillars of buildings within 30m of coastal line were toppled. The flood region had reached to lkm or more inland.<BR>(2) The tsunami height of Patong beach was about 6m on the sea level, and almost all walls and pillars of buildings within 30m of coastal line were not toppled but the flood depth was about 2m.<BR>(3) The tsunami height of Phi Phi island is 6-7m on the sea level at the north side and 3.5-5m on the sea level at the south side.
著者
鈴木 高二朗 永井 紀彦 柳嶋 慎一 久高 将信 小川 路加
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.129-133, 2008 (Released:2010-08-25)
参考文献数
8

Ocean wind is larger and more suitable for wind farm than inland wind. Recently, ocean wind farm has been constructed in Europe using 5MW wind power facility. Japan is surrounded by ocean and seems to be suitable for construction of ocean wind farm. However, the amount of the shallow and low wave energy area for ocean wind farm is limited except semi-enclosed bay like Tokyo bay.When we see Tokyo bay, shallow area (shallow more than 15m) is located north of Futtsu Point in Chiba prefecture. Such a shallow area is near to urban area, so the construction cost seems to be lower. In this paper, feasibility study on the ocean wind farm north of futtsu point in Tokyo bay is done compared with the other coasts of Japan.
著者
山本 吉道 河合 恭平 高野 哲男
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.24, pp.1339-1344, 2008 (Released:2010-08-25)
参考文献数
21
被引用文献数
2 2

In this research, the Ishikawa-ken area of Kaetsu coastal zone and Enshu-nada coastal zone are selected as the coastal zone where a large-scale sandy beach is left, and sedimentation control of those zones is examined in order to recover the continuity of overall movement of earth and sand, and the following plans are proposed:1) An efficient countermeasure based on sand recycling by shipping and natural carrying system due to waves and currents in the Ishikawa-ken area of Kaetsu coastal zone.2) An effective countermeasure based on natural carrying power due to Tenryu river flow and a sand bypass by trucking for short distance in Enshu-nada coastal zone.
著者
三上 信雄 安藤 亘 石岡 昇 大隈 篤 山本 秀一 北野 倫生
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.23, pp.925-930, 2007

To promote utilization of Okinotorishima island and its surrounding areas mainly in the fishery field, fishery resources and environmental conditions were surveyed in and around the coral reef of the island. Corals were widely distributed in the lagoon. Some useful fishery species were caught through the wide range from the surface to the deep water around the reef. Their preys such as eggs, juveniles and young of some small sized fish species were also observed there. Therefore, it may be possible to utilize the island as a good fishing ground with an artificially increased primary production. To develop this potential, some ideas and their issues to be solved in the future were discussed in this study.
著者
清野 聡子 宇多 高明 前田 耕作 綿末 しのぶ
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.431-436, 2002 (Released:2011-06-27)
参考文献数
7

Field observation of spawning ground of horseshoe crab Tachypleus tridentatus was carried out in August 2000 at a river mouth in Seikai-cho in Nagasaki Prefecture. Many eggs spawned under thegroundof river mouth bars were found. Morphological features of spawning ground including surrounding vegetations were investigated and compared with the results of the former studies. Results were well explained by the features summarized in the former studies. A note on conservation of rare species was discussed.
著者
熊田 貴之 小林 昭男
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.16, pp.315-320, 2000 (Released:2011-06-27)
参考文献数
4

In this paper, the results of the field survey on the coastal erosion at Kemigawa beach as the artificial beach are presented, and causes of the erosion are discussed using the sea conditions and the grain-size distribution of sands of the beach. The results of the investigation are summarized as follows:(1) The erosion at Kemigawa beach is intense compared with neighbor artificial beaches that has a characteristic like the Kemigawa beach.(2) The result of the numerical analysis using the cross section of the construction plan shows that the wave conditions of near shore at Kemigawa beach is calmness in the stormy weather.(3) The results of the grain-size analysis of sands show that the small-size sands that flow away from the center of Kemigawa beach maybe deposit at the base of the breakwater.(4) The result of the comparison between d50 of the sands and the gradient of the foreshore about the construction plan of Kemigawa beach shows that the beach has the tendency of the erosion.
著者
吉田 秀樹 中島 謙二郎 川野 泰広 江口 秀之 中村 義文 日向 博文
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.709-714, 2007 (Released:2010-08-25)
参考文献数
6
被引用文献数
1 2

The Kyushu Regional Development Bureau, Ministry of Land, Infrastructure and Transport has placed four High-Frequency Oceanic Radar System (HF radar) at the Ariake Sea with the aim of regenerating environmental condition, and has observed the surface current and ocean wave situations since 2005.The paper presents (1) the result of study for precision of HF radar observation, (2) the real-time informing system by internet named “The Ariake Sea current and ocean waves information system”, and (3) the development of “The sea garbage movement prediction system” utilized the surface current observation information by the system with the aims of the improving the sea garbage collecting service by the Advanced Anti-Pollution Vessel “KAIKI” as well as the progress of the installing the system. As result of the development, the precision is verified appropriately, and the system has been operated since April, 2007.
著者
北 賢二 小林 昭男 宇多 高明 野志 保仁 和田 信幸
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.409-414, 2005 (Released:2011-06-27)
参考文献数
3

Damages of wind blown sand were investigated at Makuhari artificial beach in Chiba Prefecture, the Chigasaki coast in Kanagawa Prefecture and Nakatajima Sand Dune in Shizuoka Prefecture. Fine sand was transported by wind and deposited on the promenade behind the beach, causing obstruction against traffics. In order to study these phenomena, field study on wind blown sand consideringg rain size effect was carried out at Kujukuri beach. It was confirmed that selective transport of fines and is important and this results in sorting effect in an extensive area.
著者
長尾 毅 藤森 修吾 築地 健太朗
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.201-206, 2008 (Released:2010-08-25)
参考文献数
5

The reliability-based design method was recently introduced to the technical standard for port and harbor facilities. The standard method is partial factors method, however, other methods that evaluate the reliability index directly can also be applied. Taking the design of pile supported wharves as an example, performance function is implicit and the application of the methods that evaluate the reliability index directly is difficult to the practical design. This study aims at clarifying the applicability of response surface method for pile supported wharves. As the performance function can be evaluated explicitly by the method, the calculation of reliability indices is comparatively easy. The applicability of first-order second-moment method is also discussed.
著者
本間 大輔 窪内 篤 山本 泰司 畑山 朗 木村 克俊
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.927-932, 2005 (Released:2011-06-27)
参考文献数
1
被引用文献数
1 1

On September 8, 2004, Typhoon No.0418 (Typhoon Songda) moved north along the western coast of Hokkaido, bringing high winds to wide areas in the storm zone. Omori Bridge, a 429-m-long I-girder bridge on National Highway 229, suffered the collapse of a 159-m-long section. The bridge spanned a reef that is surrounded by wave-dissipating blocks on the seaward side and precipices on the landward side. On the day of the collapse, waves were extremely high and winds were strong, and abnormal tide levels were attributed to the effect of the local topography. In this research, hydraulic model tests were performed to study the damage mechanism of the bridge and the wave forces that acted on it, in order to assess the safety of the truss bridge that will be erected for temporary restoration. The splash patterns were also examined to determine the conditions under which vehicles can safely run after the restoration.