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Volume 16 (1975)
- Issue 4 Pages 169-
- Issue 3 Pages 115-
- Issue 2 Pages 45-
- Issue 1 Pages 1-
Volume 16, Issue 3
Displaying 1-5 of 5 articles from this issue
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Atsuo TAKEUCHI1975 Volume 16 Issue 3 Pages 115-125
Published: September 30, 1975
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSJust after a landslide or landslip occurs, we can often observe in situ that ground water gushs out like a vein-stream from the main scarp or among deposits of the landslide or landslip area. By examining the relation between this phenomenon and the results of various investigations for ground water, such as tracer method, water-level, flowing layer detector, pumping test, water quality, and others, it is inferred that the ground water having a large influence on the landsilde movement or occurrence exists as the state of vein-streams in and around the landslide area.
In many cases the landslide seems to occur or move when the abnormal condition arised in vein-streams by some causes, such as heavy rain, thawing water, earthquakes, embankment, and others.
Accordingly in order to investigate the occurrence and movement mechanism of landslide or landslip phenomena, it is neccessary for us to estimate the existing places of vein-streams in and around landslide and landslip area as accurate as possible. Then the author proposed one new survey method “The underground temperature survey in one meter depth” for the vein-streams in and around them. It was shown, by both a theoretical study and experiments in situ, that this new method was useful one for surveying the ground water like a vein-stream.
By using both the new method to estimate the scales of vein-streams and some methods to obtain the displacement values of landslide soil-mass, it was found that the vein-stream had a large influence upon the landslide movement: As the scale of the vein-stream becomes larger, the displacement values of the soil mass increases; and the scale becoming smaller, the value decreases.View full abstractDownload PDF (1226K) -
Yasunori OTSUKA, Toru ONODERA1975 Volume 16 Issue 3 Pages 126-131
Published: September 30, 1975
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSThe deformation and movement developed by the geological structure in some regions yield faults, fractures, folds and so on. Teref ore approach to the strength properties of rock mass is led by the understanding of the orientations of strength anisotropy of rocks due to these geological structures.
In this paper the authors described the result of an experimental study on the change of strength and deformation characteristics with water absorption, taking their anisotropy into account. On the one hand tensile strength of rocks has been determined by the point load test on untrimmed test specimens to know the influence of water absorption to strength. On the other hand elastic wave velocities of specimens have been measured and the dynamic moduli Ed have been calculated in view of their deformation anisotropy.
The tensile strength is denoted “σta” and “σtc” respectively in the direction normal and parallel to the discontinuity planes such as joint surfaces. Similarly the dynamic modulus in the direction normal to the discontinuity planes is called “Eda” and that parallel to them “Ede”.
The results obtained as to the dynamic modulus and point load test are summarized as follows:-(1) Degree of strength anisotropy shown by point load test, “σta/σtc” and that by dynamic modulus, “Eda/Edo” correlate nearly with a straight line.(2) While degree of anisotropy of dynamic modulus “Eda/Edc” is decreased, that of strength anisotropy “σta/σtc” is increased when water is taken into discontinuity planes.View full abstractDownload PDF (492K) -
Yoshiro HAYASHIDA1975 Volume 16 Issue 3 Pages 132-140
Published: September 30, 1975
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSIn this paper the property of free swelling of artificially crushed Tertiary (Kobe, Tsuyama and Mizunami group) mudstone is discussed. The degrees of free swelling depend on the the content of active clay minerals, such as montmorillonite and vermiculite, and the water contents are decided with pF value which is determined by soil suction, i.e. The results show that the degrees of free swelling are in proportion to the content of montmorillonite minerals in a soil and the water contents at a certain soil suction except Mizunami group mudstones.View full abstractDownload PDF (670K) -
Seiya IMANISHI1975 Volume 16 Issue 3 Pages 141-149
Published: September 30, 1975
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSThe Enasan Tunnel is a vehicular tunnel with two lanes and a length of 8, 489 m from Iida city to Nakatsugawa city.
The geological survey of the Tunnel was started in 1957. On the basis of preliminary survey, many faults and sheared zones running from sounth to northward were recognized. Misaka fault have wide sheared zone about 700 m in width.
The pilot tunnel was first driven for the whole length of the tunnel. Its purpose was to explore the strata, fully and to simplify access, ventilation and drainage in the construction of the main tunnel. Geological conditions were much worse than anticipated. Tunnelers hat to bore through the mountain of granite and rhyolite crossed by over 130 faults and saturated with ground water. Maximum pressure ofgroundwater reached about 50 kg/cm2.View full abstractDownload PDF (1397K) -
Hidetoshi INOMA1975 Volume 16 Issue 3 Pages 150-156
Published: September 30, 1975
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSThis report refers to some geotechnical experiences about the shaft work in Enasan-tunnel that is lately completed.
They contain following topics.
(1) location of the shaft
(2) geotechnical investigation fer design and operation
(3) a boring for drain and attendant works
(4) excavation in distress
(5) cracks in lining due to 440 m-fault gougeView full abstractDownload PDF (1033K)
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