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
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
本島 真也 小林 昭男 宇多 高明 遠藤 将利
出版者
公益社団法人 土木学会
雑誌
土木学会論文集B2(海岸工学) (ISSN:18842399)
巻号頁・発行日
vol.69, no.2, pp.I_721-I_725, 2013 (Released:2013-11-12)
参考文献数
5

On the Oharai-Isohama coast, 1×104 m3 of gravel and 2.5×103 m3 of fine sand were nourished in April and May 2012 as a measure against beach erosion. Simultaneously tracer test was carried out using 100 m3 of granite gravel with a diameter of 20 cm, which was not deposited on the original beach. Granite gravel was placed on the shoreline, and subsequent movement was measured using GPS along with the measurement of the diameter of the gravel. It was found that gravel was transported northward and deposited on the shoreline.
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
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
星上 幸良 小林 昭男 宇多 高明 熊田 貴之 酒井 和也 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.487-492, 2003 (Released:2011-06-27)
参考文献数
4

Relation between beach erosion and the development of coastal forest was investigated by comparing past aerial photographs, taking the Heisa-ura coast in Chiba Prefecture as the example. Sand dune has been well developed at this coast due to the strong wind-blown sand in winter in the past. In order to prevent the damage due to wind-blown sand, coastal forest has been extensively planted. However, excess development of coastal forest in recent years as well as the construction of earth dike along the coastal forest caused shoreline recession by the excavation of beach sand to supply the construction materials. Appropriate land management isrequired between the coastal forest area and the shore protection area in order to avoid devastation of natural sandy beach.
著者
黒澤 祐司 小林 昭男 宇多 高明 野志 保仁 遠藤 将利 古谷 真広
出版者
公益社団法人 土木学会
雑誌
土木学会論文集B2(海岸工学) (ISSN:18842399)
巻号頁・発行日
vol.68, no.2, pp.I_1461-I_1465, 2012 (Released:2012-11-15)
参考文献数
5

In beach nourishment using gravel, the macadam gravel is used so that the sharp-pointed shape of gravel is of concerned. In this study, the change in the shape of gravels due to wave abrasion was investigated. Gravel samples were collected from the Jinkoji and Akashi coasts in Ibaraki Prefecture, where beach nourishment using coarse materials have been carried out since 2005, and grain size and roundness were measured. It was found that roundness of gravels with an initial value of 0.2 converged to 0.4-0.5 within four years and nine months. Due to the abrasion test of sampled gravels without steel bowls, the content of gravel was as high as 92% of all the volume after the rotation of 1200 times.
著者
清水 達也 小林 昭男 宇多 高明 熊田 貴之 野志 保仁 芹沢 真澄
出版者
Japan Society of Civil Engineers
雑誌
海岸工学論文集 (ISSN:09167897)
巻号頁・発行日
vol.54, pp.691-695, 2007 (Released:2010-06-04)
参考文献数
7

Topography of beach cusps and grain size sorting was observed at four coasts, as well as the observation of a backwash flow in a bay of a cusp. A movement of sea water flowing obliquely from the apex to the bay was observed, resulting in the generation of a backwash flow. On the basis of this observation, two pairs of sink and source were assumed and three-dimensional cusp topography was predicted, using the contour-line-change model considering the effect of grain size change by Kumada et al.(2005). The formation of a cusp and associated accumulation of coarse materials around the apex were well predicted.