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Volume 32 (1979 - 198･･･
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Volume 32, Issue 3
Displaying 1-8 of 8 articles from this issue
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Takehiko OHTA1980 Volume 32 Issue 3 Pages 1-8
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (1005K) -
On the impulsive force and the rate of check of drifting woods at the stockadeKunio MIZUHARA, Aritsune TAKEI, Noriyuki MINAMI1980 Volume 32 Issue 3 Pages 9-16
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThis paper describes the impulsive force and the rate of check of drifting woods at the stockade, as the second stage of a series of study on the check. In the former, the authors derive theoretically the expression relating to the value of p corresponding to the impulsive force and set up the safety section of the pier by expanding it. In the latter, the authors research experimentally on the effect of check of the stockade and make clear the mechanism of initial check of drifting woods and the relations between the rate of check and some relating factors.View full abstractDownload PDF (1011K) -
Ryohei IMAMURAM, Masami SUGITA1980 Volume 32 Issue 3 Pages 17-26
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA simulation model of debris depositing was built basing on the Random Walk Model. This is done on an alluvial fan consisting mainly of debris from the debris flows and traction. The purpose of this study is to forecast the deposit area of the debris.
This digital model consists mainly of the following three factors:
1. Calculation of the debris volume which will be supplied to a fan surface.
2. Debris deposits through debris flow.
3. Debris deposits through traction.
The Osawa Fan, located at th foot of Mt. Fuji and the fan along Katorea-sawa in Mt. Usu are the test fields in this study. According to the results of correlation, the debris flows using this simulation model resemble to the real flows. This suggests that the simulation model can be effectiue preventing the disastrous debris flowing, which is one of the serious problem in Japan.View full abstractDownload PDF (1678K) -
Tetsuya KUBOTA, Kunio MIZUHARA, Aritsune TAKEI1980 Volume 32 Issue 3 Pages 27-36
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSSabo-workes must treat steep mountain torrents, mudflow-deposit areas and so on. In such water-course many large gravels are scattered on the bed, and remove transforming the water surface. So, considering the critical conditions for traction of scattered gravels on a mountain stream bed, we should take account of the water surface effect.
In order to simplify the phenomena, mortar or glass spheres are adopted as the cobble-stones in this study and the experiments or the observations are carried out on condition that the single sphere is set in quasi-uniform flow on a wide rectangular channel bed. Besides, an applicable model of tractive mechanics are discussed, but this paper principally describes the critical conditions for a semi-submerged gravels.
Consequently, follows have gained.
1) The water surface effect i. e. wave front effect whicn means shift of fluid dynamic force acting point is one of the important factor in traction.
2) The effect of instantaneous fluid dynamic forces, in this case that of maximum fluid dynamic forces, is notable.
3) Two dimensional model of tractive mechanics is available in this study.
4) According to above model, the critical conditions for semi-submerged gravels on a steep channel bed are function of gradient, relative water depth, relative diameter, and of specific gravity.View full abstractDownload PDF (1209K) -
Hiroshi IKEYA, Shinji UEHARA1980 Volume 32 Issue 3 Pages 37-44
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSNowadays it begins to design and construct slit sabo dam which has a slit on the crown of sabodam in the hope of sediment control in our country.
But, usual study does not evaluate the effect of sediment control by slit dam quantitatively.
Then, author studied about the effect of sediment control of slit dam by hydraulic experimentaltests, and made clear the such effect and some results mentioned as follows.
1) Blocking condition of a slit dam is shown as, b/dmax ≤1.5
2) Control effect in quantity of slit dams makes 1.2times of ordinary sabo dam in the boundarycondition of slit density, 0.2≤∑b/B≤0.6
3) Effect of slit dams which constructed continuousty 23 dams is not so effectual as a single.
4) Qualitative effect of slit dams is nearly equal to the effect of ordinary sabo dams.
As a result, effect of sediment control by slit dam makes a conclusion as follows
It is a useful effect that slit dam makes possible to flow down the sediment at ordinary time andto check the sediment at the big flood.View full abstractDownload PDF (1095K) -
[in Japanese], [in Japanese]1980 Volume 32 Issue 3 Pages 45-51
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (9578K) -
[in Japanese]1980 Volume 32 Issue 3 Pages 52-54
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (350K) -
[in Japanese]1980 Volume 32 Issue 3 Pages A1-A3
Published: March 10, 1980
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (6460K)
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