Journal of the Japan Society of Erosion Control Engineering

[title in Japanese]

Kohei FURUKAWA

2004 Volume 56 Issue 5 Pages 1-2
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_1

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A study on setting a critical line of landslide disaster for warning and evacuation and effect evaluation of groundwater drainage works based the prediction model of groundwater level by neuralnetwork

Hiroaki TAKEMOTO, Atsukuni KAJIMA, Kazumasa KURAMOTO, Tsutomu HONJO, K ...

2004 Volume 56 Issue 5 Pages 3-14
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_3

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Some methods had previously been proposed to model the relationship between groundwater level and rainfall. These methods, however, involve parameter setting by trial and error and may require considerable experience in determining the structure of an appropriate prediction model. Groundwater level modeling can be simplified by using neural networks, which excel in nonlinear analysis, without considering complex parameters. This study constructs a neuralnetwork-based water level fluctuation model from rainfall and groundwater level data in a landslide area and demonstrates that the model has the ability to predict groundwater levels. Not only rainfall but also other factors that influence groundwater level are used to improve the precision of analysis. In addition, disaster prediction and the effect of countermeasures are discussed by using optimized models.

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Hydrogeomorphological Characteristics of a Deep-seated Landslide in the Harihara River Basin, Izumi City, Kagoshima Prefecture, Japan

Takashi JITOUSONO, Etsuro SHIMOKAWA, Masatoshi SAKO, Yukiyoshi TERAMOT ...

2004 Volume 56 Issue 5 Pages 15-26
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_15

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A deep-seated landslide occurred in the Harihara River basin on the western flank of Mt. Yahazu-lake, an old volcano, in Izumi City, Kagoshima Prefecture on July 10, 1997.This study aimed to examine the hydrogeomorphological characteristics of this landslide. Topographical and geological surveys, and hydrological observations were carried out in the Harihara River basin. This paper clarifies the geological structure around the deep-seated landslide site from some boring surveys. Further, the responses of discharges, electric conductivity and temperatures of river and spring water to storms, the response of the groundwater level around the landslide site, and the runoff characteristics are examined by analyses of hydrological data obtained from 1999 to 2002.The fundamental data needed to examine the mechanisms of the occurrence of this deep-seated landslide have been obtained; and enable the prediction of sites with high potential for such a landslide.

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Estimation of the Amount of Sediment Discharge from Steep Mountain Basins Using Sedimentation Data in Sabo-dams

Takeshi MIZUTANI

2004 Volume 56 Issue 5 Pages 27-32
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_27

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Regression equations for estimating the amount of sediment discharge from steep mountain basins have been derived by using 43 data of sedimentation in sabo-dams in Central Japan. Explanatory variables are topographic properties including mean basin gradient (S), maximum 3-hour rainfall intensity (P₃) and geological condition which are the major factors affecting the processes of sediment yield and transportation. Topographic properties are measured easily and quickly by using digital elevation data in a 50 m mesh. The amount of sedimentation in a sabo-dam per a unit drainage basin area and per year (q_s) is proportional to about the fourth power of S and the third power of P₃. Geology of studied areas is pyroclastics and volcanic rocks (V), granitic rocks (G), Palaeogene sedimentary rocks (T_p) and Palaeozoic rocks (P). Regression coefficients obtained for geological category are 0.22 for G, 0.35 for T_p and 0.14 for P when that for V is set at 1. The inverse number of these values indicates the relative registivity to erosion for each geology. Since the determination coefficients are about 0.9, 90% of q_s can be explained by these three factors.

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The characteristics of 1926 volcanic mudflow at Mount Tokachi, the evidences of eyewitnesses and examination of the deposited materials

Tomoyuki NANRI, Motohiro KUREBAYASHI, Takayuki YAMAHIRO, Tetsuya NATOR ...

2004 Volume 56 Issue 5 Pages 33-44
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_33

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Large-scale mudflow occurred as an aftermath of the eruption of Mount Tokachi Volcano on May 1926, and killed 137 residents in Kami-Furano town of central Hokkaido. The flowing conditions of the mudflow were investigated by interviewing survived eyewitnesses and examining remnant of the mudflow deposits, concentrating on flow velocity and depth, condition of scouring and deposition, houses destruction, and deposited materials variation according to the sites. Surveying the mudflow descent conditions, it was divided into three types as follow : Flow I, with the velocity from 11 to 17m/s, the depth from 4 to 6m and about 1000KN/m fluid dynamic force, was capable of serious destruction of houses at the foundation, Flow II, with the velocity from 5 to 9m/s, the depth from 2 to 4m and more than 100KN/m fluid dynamic force, was capable of causing a heavy collapse of houses, and Flow III, whose velocity, depth and fluid dynamic force were smaller than II, was capable of slightly destroying houses and burying them. Studying the mudflow characteristics, the flow condition was thought to be flood-like and easily flowing with huge amount of sediment, great flow velocity and density suggesting high intensity resulting to massive devastation.

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Performance-based design of Compact diameter steel cell dam with support frame

Daisuke TAKEUCHI, Takeshi IIDA, Nobutaka ISHIKAWA, Takahisa MIZUYAMA, ...

2004 Volume 56 Issue 5 Pages 45-54
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_45

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The compact diameter steel cell dam with support frame is proposed as a new type of sabo dam which has wider opening rate and higher hydraulic function than the steel cell dam. In order to evaluate the total design including impact resistance design of this new type dam, the examination of the performance-based design system is needed. In this study, the required performance analysis of environment, construction, maintenance management, structural safety, and debris flow capture was performed, and the necessity and the contents of new technical examination were extracted. Furthermore, some design examples were introduced, and it was shown that the choice of structure form increased according to the diversity of design conditions.

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Applicability of slice methods to the failure load on the top surface of steep slope

Kanji KONDO, Setsuo HAYASHI, Osamu KUSAKABE

2004 Volume 56 Issue 5 Pages 55-60
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_55

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Problems of slope stability with the critical load on the top surfaces are complex. The problems have so far been examined in the view of bearing capacity of footing by using proposed formulae such as the method of the Japan Highway Cooperation, and upper bound solutions. In application of slice methods to those problems, it is of vital to properly incorporate the inter-slice forces in the analysis. This study examines the applicability of three slice methods ; the Fellenius method, the Spencer method and the Slice-Spring method, to the problems of slope stability with the critical load on the top surfaces by comparing the ultimate bearing capacities calculated by existing formulae or analytical methods. It is revealed that the Slice-Spring method yields accurate results comparable to those by the existing slice methods. The Fellenius method also provides similar results when the internal frictional angle is zero, while the Spencer method gives smaller values of bearing capacity when the frictional angel is increasing.

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Experimental study on effect of impact force caused by earthquake on slope stability

Shinya HIRAMATSU, Megumu YOSHIOKA

2004 Volume 56 Issue 5 Pages 61-66
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_61

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Debris flow which discharged on the Shirouma-daisekkei snow patch, the Northern Japanese Alps

Kiyoteru MARUYAMA, Toshiya TAKESHI, Kazuya AKIYAMA, Shinichi KOJIMA, S ...

2004 Volume 56 Issue 5 Pages 67-71
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_67

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[title in Japanese]

[in Japanese]

2004 Volume 56 Issue 5 Pages 72-78
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_72

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[title in Japanese]

[in Japanese]

2004 Volume 56 Issue 5 Pages 79-86_2
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_79

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[title in Japanese]

Yutaka GONDA

2004 Volume 56 Issue 5 Pages 87-90
Published: January 15, 2004
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.11475/sabo1973.56.5_87

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