Journal of the Japan Society of Erosion Control Engineering
Online ISSN : 2187-4654
Print ISSN : 0286-8385
ISSN-L : 0286-8385
Volume 49, Issue 3
Displaying 1-11 of 11 articles from this issue
  • [in Japanese]
    1996 Volume 49 Issue 3 Pages 1-2
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Kanji KONDO
    1996 Volume 49 Issue 3 Pages 3-10
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    One of popular technique of preventing the slopes from collapsing is the use of anchor work. This paper discusses the determinative methods of the design anchor force and anchor body position. Generally, the design of anchor works are made use of the limit equilibrium method. On the occasion of the anchor works design using this method, it is necessary to estimating the location and shape of the slip surface. In this case, the slip surface is often adopted one of the minimum safety factor (the critical slip surface) which is determined under the condition of the slope not acted anchor force. However, the critical slip surface of the slope acted anchor force is different from one not acted anchor force, because the internal stresses of ground change owing to the anchor force. Therefore, the design of anchor force and anchor body position have to be determined under the condition of the slope acted anchor force.
    In this paper, the author shows the analytical methods and clarifies the above thought through analysing the model slopes using this analytical methods (slope stability and critical slip surface analysis) to which are applied the Spencer and the dynamic programming methods.
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  • Shinji EGASHIRA, Nobumitsu NAKA, Osamu UCHIDA
    1996 Volume 49 Issue 3 Pages 11-19
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    A method for delineating the degree of hazardous area due to landslides triggered by rainstorm is discussed. The method is developed by combining the occurrence probability of landslides and the solutions of momentum equation for sliding soil blocks on slope. It specifies the areal density distributions of kinetic energy as well as of momentum for sliding soil block, and is applied to a study area.
    The results show that the areal density distributions of kinetic energy are very useful for estimation of the degree of hazardous area due to landslides and associated countermeasures.
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  • Dexuan ZHANG, Kyoji SASSA
    1996 Volume 49 Issue 3 Pages 20-27
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Large-scale landslides were often reported in loess deposits during earthquakes. These landslides were usually rapid with high mobility. It is very important to study their mechanism of motion for landslide hazard mitigation.
    Samples were taken from loess landslides which took place during the Haiyuan Earthquake (China, 1920) . These were tested in a ring shear apparatus, and the apparent friction angle during post-failure motion was investigated. Because slip surfaces of rapid landslides are supposed to be almost under the undrained loading condition, laboratory tests were also done under undrained condition and samples were sheared for several meters of displacement. The main conclusions of laboratory tests are as follows:
    1) Under undrained condition, the sample finally approached to a steady state condition, where shear stress, pore pressure and volume were constant, and only shear displacement was increasing. The apparent friction angle mobilized at the steady state was only 6. 5 degrees. This test result can give a theoretical and experimental explanation to the high mobility of earthquake-induced-landslides in loess soils.
    2) It was found that the apparent friction angle after failure has no relationship with the OCR (over consolidation ratio) . It is shown that the apparent friction angle after failure is the strength of a new soil structure which is formed at the shearing zone during the deformation process, and the former structure has no influence on it.
    3) The apparent friction angle after failure of unsaturated loess (which in the natural state with the degree of saturation of 32. 6 %) did not decrease during a large shear displacement. The unsaturated loess layer, therefore, can not form a long run-out landslide.
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  • Yukiyoshi TERAMOTO, Takashi JITOUSONO, Etsuro SHIMOKAWA, Osamu NAGATA
    1996 Volume 49 Issue 3 Pages 28-32
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Unzen volcano had many pyroclastic flows during the period from 1990 to 1995. The pyroclastic flows were thickly deposited on the flank of the volcano. At the same time the surroundings were widely covered with a fine volcaniclastic material. As a result of those, debris flows and floods have frequently occurred at the rivers on the flank of the volcano.
    Observation stations of debris flows were established at two ravines on the flank of the volcano in order to examine the occurrence and runoff characteristics of debris flows and floods quantitatively. In this paper, the characteristics of debris flows and floods following the pyroclastic flows were analyzed using the records of debris flows and floods observed in 1995.
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  • Takashi JITOUSONO, Etsuro SHIMOKAWA, Yukiyoshi TERAMOTO, Osamu NAGATA
    1996 Volume 49 Issue 3 Pages 33-36
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Tsukasa MATSUMOTO
    1996 Volume 49 Issue 3 Pages 37-42
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Yutaka GONDA
    1996 Volume 49 Issue 3 Pages 43-45
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • Takashi YAMADA, Shigeki TANAKA
    1996 Volume 49 Issue 3 Pages 46-48_2
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • 1996 Volume 49 Issue 3 Pages 50-67
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese]
    1996 Volume 49 Issue 3 Pages 72
    Published: September 15, 1996
    Released on J-STAGE: April 30, 2010
    JOURNAL FREE ACCESS
    Download PDF (107K)
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