著者

辻本 浩史 増田 有俊 真中 朋久

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.69, no.6, pp.49-55, 2017-03-15 (Released:2018-04-09)

参考文献数

12

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It has been recognized that a linear-shaped mesoscale convective system (LsMCS) causes the localized, torrential, and stationary rainfall. In this paper, the characteristics of LsMCS during sediment disaster events are investigated using radar data which has 5 minutes time interval and 1 km horizontal resolution. To extract the LsMCS from radar data, a contiguous regions of convective cell group is identified with more than 20 mm/h of rainfall intensity and more than 300 k㎡ of the area. The shape of the convective cell group is approximated as an ellipse and the motion vector is calculated from the change of position within the consecutive radar data using the correlation coefficient method. The characteristics of the shape, motion and rotation were analyzed using radar data in sediment disasters caused by LsMCS. As the result, it was found that the criteria for detecting LsMCS are as follows. (1) The aspect ratio (major axis/minor axis) of ellipse is more than about 2.0. (2) The motion vector of the ellipse is rotated in the counterclockwise direction from the long axis of the ellipse and the angle of rotation is less than about 22.5 degree. (3) The weighted center of convective cell group is shifted to the windward side as compared to the center of ellipse.

著者

松本 直樹 和田 孝志 中谷 加奈 里深 好文 水山 高久

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.65, no.3, pp.3-11, 2012-09-15 (Released:2015-08-03)

参考文献数

19

被引用文献数

5

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Debris flow is composed of mixed-size gravel, and the grain size distribution and concentration of sediment strongly affects the flow behavior. To predict more accurate debris flows, we need a numerical model that considers mixed-size gravel and can describe sediment sorting. We propose a more accurate method for predicting mixed-size debris flow behavior, from torrents to alluvial fans. We combined a debris flow model that can describe sediment sorting with an integration model, and proposed an integrated model for mixed-size gravel. Applying this model, we simulated debris flow on a virtual watershed under different conditions of inflow sediment distribution. Our results showed that an integrated model for mixed-size gravel provide a more rational description of debris flow in torrents and alluvial fans than models of uniform-sized gravel.

著者

水山 高久 江頭 進治

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.54, no.3, pp.90, 2001-09-15 (Released:2010-04-30)

著者

山田 隆二 木村 誇 苅谷 愛彦 佐野 雅規 對馬 あかね 李 貞 中塚 武 國分(齋藤) 陽子 井上 公夫

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.73, no.5, pp.3-14, 2021-01-15 (Released:2022-01-17)

参考文献数

46

被引用文献数

1

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Establishing chronologies for large-scale landslides is crucial to understand the cause of the mass movements and to take measures against potential hazards in future. We discuss the applicability of dating methods for determining landslide chronologies in relation to the type of samples and the stratigraphic setting of sampling location. Case studies are carried out with fossil wood samples buried in the deposits of large-scale landslides in two areas of the Japanese Alps region in historic times ; Dondokosawa rock avalanche (DRA) and Ohtsukigawa debris avalanche (ODA). Ages are determined by accelerator mass spectrometry radiocarbon dating and dendrochronological analysis using the oxygen isotope composition of tree ring cellulose. We report seven radiocarbon ages and five dendrochronology data for the wood samples taken from outcrops and excavated trenches in the lacustrine sediments of dammed lakes formed by DRA, and two radiocarbon ages and two dendrochronology data for wood samples of ODA. Two sets of data for DRA are crosschecked independently to ensure the accuracy of results. Most of ages in the DRA area are concordant with the period of AD 887 Ninna (Goki-Shichido) mega-earthquake as proposed in previous studies. In the ODA area, ages are not concentrated in a specific period. When the preservation condition of buried wood trunks is good enough to date the exact or approximate tree-death years dendrochronologically, it is possible to estimate landslide occurrence periods in further detail by comparing the landslide chronology with historical records of heavy rainfall and large earthquakes.

著者

田中 義紘 内山 敦史

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.50, no.5, pp.89-91_2, 1998-01-15 (Released:2010-04-30)

参考文献数

4

著者

鈴木 雅一

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.64, no.5, pp.38-42, 2012-01-15 (Released:2015-02-02)

参考文献数

6

著者

林 真一郎 水野 正樹 佐藤 匠 神山 嬢子 岡本 敦 吉川 知弘 鵜殿 俊昭 横田 浩 野田 敦夫 吉川 和男

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.66, no.3, pp.32-39, 2013-09-15 (Released:2015-11-30)

参考文献数

9

被引用文献数

1

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We tried to establish the detection methodology by viewing single high resolution synthetic aperture radar (SAR) satellite images which are now available. At first, a check list was made to qualitatively evaluate if it is or is not possible to detect landslide dams. By using that check list, high resolution SAR satellite images (TerraSAR-X, COSMO-SkyMed, RADARSAT-2) of Talas disaster in the Kii Peninsula have been evaluated. We confirmed conditions suitable for satellite as follows. All direction radar can detect landslide dams. The radar angle range suitable for obtaining images is from 35 to 50 degrees. Suitable image resolution is 3m. All sensors and bands are capable of detecting landslide dams.

著者

北野 靖

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.50, no.4, pp.64-67_2, 1997-11-15 (Released:2010-04-30)

参考文献数

3

著者

木下 篤彦 坂井 佑介 大野 亮一 田畑 三郎 川島 正照 山崎 孝成

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.65, no.5, pp.11-20, 2013-01-15 (Released:2015-08-03)

参考文献数

11

被引用文献数

8

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Tree roots with an underground lateral network play a very important role in slope stability. In studies such as those by Tsukamoto(1987)and Abe(1997), the authors focused on roots that have a vertical connection between the surface soil layer and below, but they did not place much emphasis on the lateral spread of roots. Because slope failures occur in three dimensions, horizontal roots fully demonstrate their resistance against the failure. This paper aims to describe the resistance force Δ C that lateral roots provide. Two types of field investigations were made. One was the root pulling test to monitor the strength of a root pulled by a clamp. The other surveyed the lateral root distribution exposed in vertical sections excavated in the plots of Japanese cypress and cedar forests. The observed root distribution was used to calculate the resistance force Δ C. The field data show that as the distance between two trees increases, the Δ C value gets smaller. Their relationship can be described by a negative power function. It has also been proven that as the age of a tree increases so does the Δ C, but its increment gets smaller in the later stages of the tree's lifecycle. Intensive work with the field data has shown that forest thinning operations might decrease the root volume after felling and bring about an increase of Δ C that lasts for several decades. Moreover, thinning operations produce good results in slope stability when lateral roots are effectively increased. However, if the increase is insufficient, it might not contribute to slope stability.

著者

藤井 昭二

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.49, no.6, pp.3-8, 1997-03-15 (Released:2010-04-30)

参考文献数

25

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The Tateyama volcano is located in the central part of the Japanese Islands and situated on the northern part of Norikura volcanic zone.Volcanic activities of the Tateyama volcano in the late Quaternary, were classified into four stages. Andestic lava and pyroclastic materials were erupted during those activities. Eruption of the second stage produced so many pyroclastic materials as forming caldera. Afterwards this caldera was eroded and grew larger. A part of caldera wall was broken at Shiraiwa about twenty thousand years ago, and as the result, a lot of debris flowed over the caldera into Joganji River. The Tateyama Sabo Work is one of the largest Sabo work in Japan. Its most important work is the control of the Tombidoro which was produced by the deformation of the Tombiyama (Mt. Tombi) in the earthquake induced by the Atotsugawa fault in 1858. Deformation of the caldera wall by the earthquake may have occurred at any place in the caldera. But why did Tombi collapse occur at Tombiyama? From investigating topography of Kanayamadani and the Tombi collapse, I may conclude the cause of Tombi collapse is that Tombiyama was the terminal place of the right lateral Atotsugawa fault, and force of tension stress and depression concentrated here.

著者

渡辺 敞 徳山 久仁夫 中山 政一 二宮 寿男 大八 木俊治

出版者

社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.31, no.3, pp.22-30, 1979

被引用文献数

2

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土石流災害から人命を守るための防災体制づくりの一環として,昭和50年台風5号時の仁淀川流域を調査し,警戒・避難基準雨量を設定する手法を検討した。<br>土石流発生時刻を現地で聞き取り調査し,降雨データと併せて発生時の目安雨量を定めた。豪雨時のモデル降雨をハイエトグラフを用いて設定し,土石流発生目安雨量に達する2時間前と1時間前の累加雨量をそれぞれ警戒と避難の警報を発する基準雨量とした。<br>その値を既往の豪雨に適用した場合の適合度を検討した。

著者

平川 泰之

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.58, no.6, pp.18-22, 2006-03-15 (Released:2010-04-30)

参考文献数

7

被引用文献数

1

著者

石井 崇 西村 友之 間野 達 澤樹 征司 長井 斎 鈴木 荘司

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.68, no.6, pp.01-02, 2016-03-15 (Released:2017-03-21)

著者

下江 勉 恵柳 信政

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.30, no.3, pp.22-27, 1977-12-20 (Released:2010-04-30)

参考文献数

6

著者

高梨 和行 花房 秀俊 松田 和男

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.50, no.1, pp.45-51, 1997-05-15 (Released:2010-04-30)

参考文献数

14

著者

山田 孝

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.48, no.4, pp.49-57, 1995-11-15 (Released:2010-04-30)

参考文献数

21

著者

鈴木 雅一

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.65, no.1, pp.03-03, 2012-05-15 (Released:2015-08-03)

著者

寺田 一之 水谷 嘉孝

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.56, no.1, pp.37-44, 2003-05-15 (Released:2010-04-30)

参考文献数

2

著者

古川 浩平 松本 幸太郎 大石 博之 円田 竜太 井上 佳子

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.61, no.3, pp.15-26, 2008-09-15 (Released:2013-09-02)

参考文献数

12

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In erosion control engineering field, various kinds of new techniques have been developed and briskly put into practical uses. Among these techniques, it is said that non-structural measures have been in demand lately. These measures contain many kinds of techniques and the terminology “non-structural measures" that are still not clear. Therefore, in this study, various kinds of non-structural measures which have been developed so far are reviewed, and the present technological development measures are analyzed in relation to social demands. As a result, practical needs on these measures, today and in the future, will be clarified. This paper's distinctive feature is its analysis based on the quantity of patent right registration, while in many preceding papers, major analyses used to be conducted based on the quantity of academic papers. Additionally, the questionnaire survey or the hearing investigation was executed to extract the problem that the erosion and torrent control field had, and it listened to engineer's opinion and manager's opinion at the technology development. From the result of this investigation, it turned out to be felt that the entrepreneurial strategy and the advantage of making to the patent are different.

著者

森 俊勇 井上 公夫 水山 高久 植野 利康

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:02868385)

巻号頁・発行日

vol.60, no.3, pp.44-49, 2007-09-15 (Released:2010-04-30)

参考文献数

21

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As many as 19 landslide dams have been formed in the northern region of Nagano prefecture, central Japan, in last 500 years except one case. Of this number, seven were formed when the Zenkoji Earthquake occurred in 1847. This abundance is likely because of the geotectonic background of this area which is located at the western end of the “Fossa Magna, ” or Japan's central graben belt.The Tobata landslide occurred in the early morning of June 24, 1757 due to heavy rain. Blocking the Azusa River, which is upstream of the Shinano River, a landslide dam with a height of 130 m and a storage capacity of 85 million m3 was formed. Around 10 a.m. on the third day (54 hours later), this landslide dam burst and its water flooded the area up to the confluence with the Narai River. According to calculation using the Manning's formula, it is estimated that the flood water ran down the river in a concentrated path with a velocity of 12 m/s and a peak flow of 27, 000 m3/s.When the dam burst, local people were quickly ordered to evacuate and no casualties were caused during this flood.