著者

池谷 浩

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.29, no.4, pp.24-28, 1977-05-15 (Released:2010-04-30)

参考文献数

8

著者

鈴木 拓郎 堀田 紀文

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.1, pp.13-24, 2015

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<p>The shallow water equations are generally used for numerical simulation of debris flows. In this method, the distributions of the flow velocity <i>u </i>and sediment concentration <i>c </i>are vertically averaged. Therefore, the calculation may be inaccurate when the upper and lower layers have different flow directions, as with countergradient flows. We propose a numerical simulation method for calculating the vertical distributions of <i>u </i>and <i>c </i>in debris flows. Our method is based on the moving particle semi-implicit (MPS) method, which was originally used for incompressible viscous fluid flows with free surfaces. Some modifications are necessary to adapt the method for debris flows. We introduce the constitutive equations of Egashira et al. to the MPS method. In Egashira's equations, debris flows are treated as a continuum. Thus, the proportion of gravel in a debris flow is expressed using the variable <i>c</i>. Similarly, each particle has an associated <i>c </i>value in our modified MPS method. In Egashira's sediment concentration equations, the equilibrium vertical distribution of <i>c </i>is obtained by integrating the rate of change of <i>c </i>in the vertical direction from the riverbed. In our method, <i>c </i>values spread among nearby particles, in order to reduce the difference between the equilibrium rate of change <i>c </i>and the actual rate of change of <i>c</i>. Numerical simulations of debris flow are performed. In the equilibrium condition, there is good agreement with the vertical distributions of <i>u </i>and <i>c </i>and those derived from the constitutive equations. In the condition where the riverbed gradient becomes less steep, there is good agreement with experimental results with a very short relaxation time, including those involving the formation of a convex upward deposition shape in the initial deposition process. Results for the initial deposition process are not produced with existing simulation methods that are based on the assumption of local equilibrium of average sediment concentration. However, simulations with a very short relaxation time show that local equilibrium is established as well as in existing methods. This indicates that the assumption of local equilibrium of sediment concentration is correct, and that because it evaluates the local equilibrium of each particle, our model can yield good results.</p>

著者

池谷 浩 石川 芳治

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.45, no.3, pp.52-56_2, 1992-09-15 (Released:2010-04-30)

参考文献数

3

著者

山下 祐一 石川 芳治

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.44, no.2, pp.22-25, 1991-07-25 (Released:2010-04-30)

参考文献数

13

著者

西本 晴男

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.59, no.1, pp.39-48, 2006-05-15 (Released:2010-04-30)

参考文献数

72

被引用文献数

2

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Debris flow had been called in the various ways in Japanese, such as “Yama-tsunami”, “Yama-shio”, “Oshidashi”, or “Teppou-mizu”. This paper shows how the debris flow has been called academically, administratively, linguistically, or in journalistic ways. There are differences in transitions in the expressions of debris flow between academic, administrative, linguistic or journalistic ways. For example, “Doseki-ryu” was firstly used in the textbook of the Sabo engineering in 1916, while newspapers generally began to use “Doseki-ryu” in mid-1970 s. Until mid-1970 s, they used “Yama-tsunami” or “Teppou-mizu”. These transitions were executed with regard to the historical and social backgrounds.Here I also examined the origin of “Doseki-ryu” using literatures of France and Austria, because these countries had already done many studies about debris flow in 19th century. Based on these investigations, it can be thought that “Doseki-ryu” was composed by combining “doseki (stones and soils)” and “ryu (flow)”. While, other terms, like “Yama -tsunami”, are metaphoric expressions, “Doseki-ryu” can be considered to be very reasonable technical term, in terms of situation of occurrence, flow materials, behaviors of flow and linguistics.

著者

廣井 脩

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.51, no.5, pp.64-71, 1999-01-15 (Released:2010-04-30)

参考文献数

4

被引用文献数

2

著者

黒岩 知恵 平松 晋也

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌

巻号頁・発行日

vol.63, no.4, pp.16-21, 2010

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Many hillside landslides and debris flows occurred by typhoon T 0421 in Miyagawa village (the present Odai town) on September 29, 2004. These caused severe sediment-related disasters. In this study, several findings on the influence of precipitation, slope angle and forest practice on hillside landslides caused by typhoon T 0421 were shown in Miyagawa-dam basin as follows : 1) Correlation between precipitation and collapsed area ratio was not clear. 2) Angle of collapsed slope in deforestation sites was 5-10° lower than those of non-forestation and reforestation sites. 3) Collapsed area in deforestation sites occupied 57% in total collapsed area. 4) Most of landslides were occurred since 10 to 20 years after deforestation. 5) More hillside landslides observed in larger deforestation area. 6) A prediction model of slope stability changes considering forest practice (Kuroiwa and Hiramatsu, 2004) was applicable to Miyagawa-dam basin. As the result of this simulation, collapsed area is generally in proportion to collapsing possibility area ratio index (APhr(t)). 7) Angle of collapsed slope and APhr(t)and collapsed area ratio showed significant correlation.

著者

KIM Suk Woo LEE Jin Ho CHUN Kun Woo

出版者

公益社団法人 砂防学会

雑誌

International Journal of Erosion Control Engineering

巻号頁・発行日

vol.1, no.2, pp.44-53, 2008

被引用文献数

3

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Recent climate change caused by global warming has affected the environment in Korea, resulting in increased precipitation and frequency and magnitudes of typhoons. From 1994-2003, a mean of 2.3 days/year experienced heavy rainfall (&ge;80 mm), in contrast to a mean of 1.6 days/year from 1954-1963. Of the ten typhoons that have resulted in the maximum daily rainfall over the last ten decades, seven occurred between 1990 and 2007. The maximum instantaneous wind velocity of typhoons has greatly increased from 20 m/sec (in the 1970s) to 40 m/sec (in the 2000s). Furthermore, increases in the occurrence and scale of forest fires and landslides, as well as increased infrastructure and land use, contribute to sediment disasters. Accordingly, environmental changes and human-induced factors have resulted in significant increases in the magnitude and frequency of natural disasters, especially in the Gangwon region on the east coast of Korea. Therefore, in 2004 the Korea Forest Service instituted an integrated and environmentally-friendly system for forest management, which has helped prevent sediment disasters. Multiple prevention strategies are also required in addition to these systemic changes to forest structure management, including control of hill-slope erosion and torrent erosion, debris flow mitigation, water storage and slit dams, grade-stabilization structures and forest improvement, and watershed management.

著者

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.70, no.2, pp.76, 2017-07-15 (Released:2018-07-17)

著者

谷 勲

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.29, no.4, pp.29-38, 1977-05-15 (Released:2010-04-30)

参考文献数

4

著者

中川 達也 荒木 孝宏 三輪 賢志 石井 靖雄 小川 紀一朗 千葉 達朗 佐野 寿聰

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.62, no.2, pp.56-59, 2009-07-15 (Released:2014-02-01)

参考文献数

8

著者

石黒 達也

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.51, no.1, pp.55-59, 1998-05-15 (Released:2010-04-30)

参考文献数

6

著者

井口 正一

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.51, no.2, pp.45-52, 1998-07-15 (Released:2010-04-30)

参考文献数

4

著者

南里 智之 槇納 智裕 米川 康 原田 憲邦 安藤 裕志 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.60, no.5, pp.23-30, 2008-01-15 (Released:2010-04-30)

参考文献数

24

被引用文献数

2

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A volcanic mudflow chronology spanning the past 40, 000 years was developed for the Furano River, which is located on the foot of Mt. Tokachi, using stratigraphic analysis, radiocarbon dating, dendrochronology and historical archives. Mt. Tokachi is one of the most active volcanoes in Japan, and its volcanic eruptions have often caused large-scale mudflows like the 1926 event that caused 144 deaths along the Furano and Biei Rivers. To develop local programs for preventing volcanic disasters, knowledge of past disasters accompanied with volcanic mudflow chronologies are required. We have identified 14 total mudflows during the past 40, 000 years that occurred along the Furano River, including events in A.D. 1926, AD. 1857, AD. 1740, A.D. 1150-1690, A.D. 600-900, 1, 900 YBP, two in 2, 000-2, 300 YBP, 3, 200 YBP, 3, 500 YBP, 3, 700 YBP, 7, 500 YBP, 13, 500 YBP, and 39, 000 YBP. Some of them were also crosschecked with historical archives. Of the fourteen mudflows, a total of 11 occurred during the past 4, 000 years, and 8 occurred during the past 2, 000 years. These high-frequency mudflows aggraded the valley channel and riverbed to the elevation of Kami-Furano City's central part, which was not damaged by the 1926 mudflow. Therefore, the next mudflow will easily reach the city's center and increase overall damage. It is generally suggested that the frequency and magnitude of volcanic mudflows will work synergistically in increasing the risk of sediment disasters.

著者

桐山 貴俊

出版者

公益社団法人 砂防学会

雑誌

砂防学会誌 (ISSN:21874654)

巻号頁・発行日

vol.68, no.3, pp.43-46, 2015-09-15 (Released:2017-03-21)

著者

沼本 晋也 鈴木 雅一 太田 猛彦

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.51, no.6, pp.3-12, 1999-03-15 (Released:2010-04-30)

参考文献数

27

被引用文献数

2

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We investigated the trends in the number of persons killed or missing by sediment disasters such as landslides and debris flows in the last fifty years in Japan. Since sediment disasters initiated by earthquakes and volcanic activity occurred intermittently and the deaths and missings caused by them were much less than caused by rainfall-triggered sediment disasters, it is appropriate to discuss trends in the number of persons killed or missing by heavy-rainfall related sediment disasters compared with trends in rainfall-triggered disasters including flood disasters. The number of persons killed or missing by both sediment disasters and heavy-rainfall related disasters has apparently been decreasing. The number of persons killed or missing by heavy-rainfall related disasters calculated as a ten-year running average exceeded 1000 persons/year in the 1950 s, 300 persons/year in the late 1960 s, and 100 persons/year in the 1990 s. Furthermore, the ratio of heavy-rainfall related sediment disaster victims to the heavy-rainfall related disaster victims has decreased from 2/3 in the 1970 s to 2/5 after the 1980 s.

著者

春山 元寿 下川 悦郎

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.4, pp.33-38, 1978-04-10 (Released:2010-04-30)

参考文献数

10

著者

池田 暁彦

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.3, pp.57-63, 2011-09-15 (Released:2015-02-02)

参考文献数

20

著者

海堀 正博 石川 芳治 里深 好文 松村 和樹 中谷 加奈 長谷川 祐治 松本 直樹 高原 晃宙 福塚 康三郎 吉野 弘祐 長野 英次 福田 真 中野 陽子 島田 徹 堀 大一郎 西川 友章

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.67, no.4, pp.49-59, 2014-11-15 (Released:2016-12-01)

参考文献数

5

被引用文献数

4

著者

宮越 英紀

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.38, no.2, pp.28-30_2, 1985-07-20 (Released:2010-04-30)

参考文献数

3