All issues
Volume 38, Issue 1
Displaying 1-4 of 4 articles from this issue
- |<
- <
- 1
- >
- >|
-
Takahiko KAKUDA, Isao MOTOJIMA, Takaji NOZAKI1997 Volume 38 Issue 1 Pages 2-12
Published: April 10, 1997
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSA large rock slope failure, such as landslide, has heavy influence on the construction and maintenance of public structures in Japan, which is mainly consist of mountainous, hilly regions. There have been much conducted the investigations and countermeasures of the rock slopes after their movement had occurred, and the useful knowledge of rock slope stability has been accumulated through those experiences. But, because the method to specify an unstable slope among many slopes before their movement occur has not been established yet, we are often troubled with the situation to judge whether more detail investigation for the slope will be necessary or not.
In this study, the geographical and geological features of rock slope failures were clarified collecting by indoor and/or field exploration from the about 100 samples of unstable rock slopes. Also, a numerical rating system to specify an unstable rock slope and to evaluate the stability of it was proposed based on above featuresView full abstractDownload PDF (1495K) -
Yoshitada MITO, Kohkichi KIKUCHI, Isamu HIRANO, Hideto NAMIKI1997 Volume 38 Issue 1 Pages 13-24
Published: April 10, 1997
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSThe observational construction method is becoming increasingly important for the active supporting plan of rock slope. As a theory for the observational construction method Stochastic Block Theory has been suggested by the authors in order to calate the probability of the event which a removable block is formed by the next excavation by taking rock joint distribution into account. In this study the applicability of this theory to the actual rock slope is examined using the joint trace maps which are obtained from the actual field. As the result of the simulation, it is clarified that this theory is useful for the prediction of a removable block.View full abstractDownload PDF (2788K) -
Yoshinori TANAKA1997 Volume 38 Issue 1 Pages 25-33
Published: April 10, 1997
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSA large number of cracks occured on a revetment of a levee in the Kobe district by the Hyogo -ken Nanbu Earthquake. Among them, low angle cracks will be payed more attention as they might be related to the surrounding ground displacement and deformation. They are classified into 5 types by their form and presence of shear displacement. Four types of them have shear displacement along the cracks in line with the river, but remaining one has not any shear displacement. The origin of low angle cracks is not at all the same and in some cases they are affected by faulting. However, it is estimated that most of the cracks were caused by the larger displacement of subsurface ground under the surface layer, taking into consideration the viewpoint of ground movement, topography and the impact test of a sand layer model.View full abstractDownload PDF (2060K) -
Isao SHIOZAKI, Shinji TANAKA1997 Volume 38 Issue 1 Pages 34-43
Published: April 10, 1997
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSThis paper shows the results of investigation of radon concentration and ionic composition (Na+, K+, Ca2+, Mg2+Cl-, SO42-, HCO3-, NO3-) of leakage water and reservoir water at the initial filling of Nishonai Dam in Aomori Prefecture. Nishonai Dam is a rockfill dam constructed in a tuff and hot spring area.
The results showed that the nitrate concentration of leakage water was very high, and the typical influence of filling of the reservoir was the decrease of nitrate concentration of leakage water caused by the intrusion of reservoir water. Therefore, the monitoring of nitrate concentration can be taken as an effective way to detect the arrival of the reservoir water at Nishonai Dam.
The variation of radon concentration showed that the influence of filling appeared on the bed rock under the core and filter zone more rapidly than the bed rock under the rock zone.
There are large differences on water quality between leakage water and reservoir water, which indicate that the flow velocity of leakage water from the reservoir is very slow.View full abstractDownload PDF (1564K)
- |<
- <
- 1
- >
- >|