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Volume 34, Issue 1
Displaying 1-3 of 3 articles from this issue
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Masayuki IMAIZUMI, Mutsuo TAKEUCHI, Takami KOMAE1993 Volume 34 Issue 1 Pages 1-13
Published: April 10, 1993
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSDipole-dipole electric surveys, radon measurements in soil-gas and γ-ray spectrometry were carried out over the Atera active fault in Yamaguti village, Nagano Prefecture. The method for measuring radon in soil-gas are granular activated carbon in thin cylindrical canister.
The results of radon measurements are correlated with the underground structure by electric survey and the γ-ray spectrometry. The underground structures in a pseudo-profiles of specific resistance contour show faults as a trace connected margin to margin of high specific resistance zones. From similar specific resistance patterns, we could find out several faults.
Several peaks over Atera faults appeared in the profile of radon concentration along survey line A. The highest radon concentration peak corresponds to the one of faults estimated from electrical prospecting.
Comparing the radon concentration to equivalent γ-ray spectrometry shows a poor correlation between radon concentration and γ-ray activities of 214Bi.The poor correlation seems to be due to that γ-ray activities 214Bi is reflecting uranium content of soil particles and radon concentration is radon content of soil-gas in pore space of soil.View full abstractDownload PDF (2223K) -
Parametric Estimation and ModellingKokichi KIKUCHI, Yoshitada MITO, Makoto HONDA1993 Volume 34 Issue 1 Pages 14-24
Published: April 10, 1993
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSBased on the probabilistic space model which is defining the distribution of joint characteristic elements [1) orientation, 2) persistence, 3) density, 4) aperture, 5) filling, 6) roughness and 7) conductivity], the authors suggest the stochastic point-estimation and interval-estimation method is to generate the joint traces or joint disks in two dimensional area or three dimensional space, respectively, considering probabilistic space of each joint characteristic element.View full abstractDownload PDF (1136K) -
Motohiko TADA1993 Volume 34 Issue 1 Pages 25-33
Published: April 10, 1993
Released on J-STAGE: June 04, 2010
JOURNAL FREE ACCESSAny inclined plane can be drawn on a equalangle stereonet (Wulff net) as a great circle. As well as the great circle, a straight line connecting two centers of the stereonet and the great circle represents both angle and direction of dip of the plane, although length of the line become shorter when the dip angle increases. This line, hereafter termed as Angle Line, is useful as a tool of analyzing rock slides.
A slope which bedrock is constructed of two geological separations is defined as the wedge type bedrock slope, and those two separations as the wedge type geological separations. Then, if the plunge of the line of intersection made of the wedge type geological separations is larger than the, angle of sliding friction, and if the line plunges toward the downslope but not the upslope side, failure by sliding should occur in association with opening of the geological separations. When each of those two discrete surfaces forming a wedge type bedrock slope is termed as the geological separations I and II, respectively, plunge and trend of the intersecting line can be calculated with the following equations:
where i is plunge of the line of intersection, β1 is dip of the geological separation I.β2 is one of the geological separation II, and λ, is angle between strikes of the geological separation I and II.And,
where γ is angle between the trend of above intersecting line and the dip of the geological separation I.
Following four examples of small-scale rock sliding failure found within Iwate Prefecture, in which failures by wedge type rock sliding is included together with those by plane (plate) type rock sliding, were invetigated;
(1) Failure of bedrock slope at the back hill of Iwate prefectural baseball ground.
(2) Rock sliding failure along Route 396 at Sahinai Shiwa town.
(3) Rock sliding failure at the back hill of Hotel Komyoso, Dai Spa, Hanamaki city.
(4) Rock sliding failure at a woodland path in Yokota-cho, Rikuzen-Takada city.View full abstractDownload PDF (1560K)
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