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Volume 47 (1994 - 199･･･
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Volume 47, Issue 4
Displaying 1-11 of 11 articles from this issue
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[in Japanese]1994 Volume 47 Issue 4 Pages 1-2
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (318K) -
Fujika KOBAYASHI, Sumiji KOBASHI, Takahisa MIZUYAMA1994 Volume 47 Issue 4 Pages 3-8
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSPublic works intend to harmonize with surrounding landscape and nature these days. It is difficult to evaluate these plans and to compare each other. The method to evaluate building plans in a city is firstly introduced, which was developed in the United States. The method is modified for sabo works. Many items are checked and evaluated with the model. It is still qualitative but it helps to compare plans each other.View full abstractDownload PDF (3308K) -
Guogiang OU, Takahisa MIZUYAMA1994 Volume 47 Issue 4 Pages 9-13
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe sediment concentration of debris-flows which continually develop while running down steep channels were studied. A debris-flow was generated in an experimental flume and its erosion rate was measured. An empirical equation was proposed based on the erosion rate and the condition of debris continuity, using the channel gradient as major parameter.View full abstractDownload PDF (634K) -
Morphological Study on Conservation of Microtopographies for Ecotechnology in Tidal Section of RiverHirokazu KITAMURA1994 Volume 47 Issue 4 Pages 14-22
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn tidal section of river, erosion control works associated with improvement of water quality are necessary, because riparian scour has been caused by daily and biweekly fluctuation of tidal level and water pollutants such as nutrient and several organic chemicals tend to accumulate. Therefore, the purpose of this paper is to establish the basic direction of conservation of the tidal river environment by utilizing ecosystem based on sabo works. It is shown by photointerpretation and ground survey that using a series of groins suits with the characteristics of river basins for flood control on tidal section, the diverse area consisting of several microtopographies are designed on the riparian zone. These area such as tidal flats, channel bars, marsh, and lagoon play a significant role in removal of nutrient loading, the self-purificative function of natural area must be considered and utilized for wastewater treatment. Therefore, it is important to conserve microtopographic environments in the tidal section of the river for improvement water quality by erosion control works and planting works.View full abstractDownload PDF (6928K) -
Yoshiharu ISHIKAWA, Shinichi KUSANO, Tosihiro KAKIMOTO, Akihiro MORITA1994 Volume 47 Issue 4 Pages 23-27
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDebris-flow braker screen dam is the facility against debris flow, it segregates sediments and water from running down debris flow, so that have been reduced its running speed, then stopped and desposited boulders and much soil.
This Debris-flow braker's screens are the trapezoidal steel pipes that are new development products considered these function and maintenance.
This experimental study is the examination strength characteristics of this trapezoidal steel pipe from static and dynamic loading tests.
So we make the proposal relation formula between the pipe's deformation and the impact energy of the boulder in debris flow from the results of these tests.
This relation formula applies to the deformation gages of the setting up Debris-flow braker's screens at Noziri-river in Sakurajima, so it's estimated that impact energy is about 8. 71t·m, and impact pressure is about 40tons for changing to the static load.View full abstractDownload PDF (633K) -
Yoshinobu TANIGUCHI1994 Volume 47 Issue 4 Pages 28-35
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe mechanism of the fluidization of a volcanic ash deposit was investigated from the view-point of liquefaction in this study. When the concentration of a volcanic mud flow is under 60%, fluidization is greatly accelerated by vibration. If a vibration of 1. 7cycle/sec-7. 3cycle/sec and an amplitude of 1cm-2cm is applied to a volcanic ash deposit with a concentration of about 50%, it will become entirely fluid in a few seconds after the start of the vibration. In a volcanic mud flow with a concentration under 48. 5%, a mixture of gravel lowers fluidity greatly. In the case where the concentration is over 48. 5%, a mixture of gravel in a volcanic mud flow increases fluidity very much. The greatest fluidity of a volcanic mud flow appears with a 40% mixture of gravel. When the movement of a volcanic mud flow becomes steady after the start of its flow, its shearing resistance force drops to about 1/9 of the earliest force after the beginning of that movement. Assuming this rate of decrease, it is possible to calculate the gradient of a channel slope corresponding to the movement of the volcanic mud flow at 2°, even though the critical value for its occurrence is 20°. This is the reason why most volcanic mud flows run down in channels with very gentle slopes in the rivers of Mount Sakurajima.View full abstractDownload PDF (3240K) -
Kazuhiro TAKAO1994 Volume 47 Issue 4 Pages 36-38
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
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Takahisa MIZUYAMA, Junji NAKAMURA, Hikoshichi ABE1994 Volume 47 Issue 4 Pages 39-43
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSFish ladders for low drop structures; groundsels have been relatively successful. Those for sabo dams are not as easy to construct because of their height. It is impossible to prepare fish ladders that work not only after sedimentation but also before dams become filled with sediment. A new idea for sabo dams with fish ladders is proposed, in which the ladders work both before and after sedimentation of the sabo dams. The key is the availability of fish ladders with steep gradients. The flow in fish ladders was examined through hydraulic test models with and without feeding sediment. The idea looks promising though it has not yet to be examined with real fish in the field.View full abstractDownload PDF (9327K) -
Masaaki NAKAYASU, Kazuyuki IMAI1994 Volume 47 Issue 4 Pages 44-48
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
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[in Japanese]1994 Volume 47 Issue 4 Pages 49-54_2
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
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[in Japanese]1994 Volume 47 Issue 4 Pages 55-56
Published: November 15, 1994
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (314K)
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