Journal of the Japan Society of Engineering Geology
Online ISSN : 1884-0973
Print ISSN : 0286-7737
ISSN-L : 0286-7737
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Volume 51, Issue 4
Displaying 1-3 of 3 articles from this issue
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Original Article
  • Influence of Facies and Microscopic Structures on Resistance of Sandy Ground against Seepage Water
    Takeshi KAWAGOE, Takuya URAKOSHI, Takehiro OHTA
    2010 Volume 51 Issue 4 Pages 170-180
    Published: 2010
    Released on J-STAGE: March 31, 2013
    DOIhttps://doi.org/10.5110/jjseg.51.170
    JOURNAL FREE ACCESS
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     A collapse of a tunnel face by seepage water often occurs in sandy ground. In previous studies, a resistance of sandy ground against seepage water was studied in view of soil mechanics. In addition, it was conceivable that the resistance of sandy ground against the seepage water was influenced by geological conditions. However, the influence of geological conditions was not studied. Therefore to understand geologic factors on the resistance of sandy ground against the seepage water, we examined soil physical properties and observed facies and microscopic structure of undisturbed sandy samples obtained from Pleistocene sand layers. The resistance of the sandy ground against the seepage water had good correlation with the clay content, the coefficient of uniformity and the cohesion. As a result of examining geological factors concerning to these physical properties, it became clear that the coefficient uniformity was related with sedimentary environment. Moreover the cohesion was different by the amount of clay minerals and cement materials covering up sand fabrics, and it was affected by the diagenesis. We concluded that sedimentary environment and diagenesis influenced the resistance of the sandy ground against the seepage water.
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  • Effect of Weathering on Changes of Leaching Properties and Chemical Forms of Heavy Metals in a Sedimentary Rock of Tatsunokuchi Formation
    Koichi SUTO, Tsuyoshi YONEDA, Yasumasa OGAWA, Ryoichi YAMADA, Chihiro ...
    2010 Volume 51 Issue 4 Pages 181-190
    Published: 2010
    Released on J-STAGE: March 31, 2013
    DOIhttps://doi.org/10.5110/jjseg.51.181
    JOURNAL FREE ACCESS
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     In this study, effect of weathering on changes of leaching properties and chemical forms of heavy metals was investigated through a laboratory scale weathering experiment using several geological samples obtained from some outcrop Tatsunokuchi formation which was distributed widely in Tohoku area of Japan as a marine sedimentary layer. At the case of the weathered samples on an outcrop, Cd leached was higher than not weathered samples and above the Japanese regulation regarded Soil Contamination Countermeasures Act. Cd existed in the sample as “exchangeable fraction”, which could dissolve easiest into water. Through a laboratory scale weathering experiment using not weathered sample, the leached Cd concentration become bigger and pH of the leachate decreased dramatically. The form of Cd was changed to “exchangeable” from “residue fraction”. On the other hand, form of As was changed to “iron—oxidized fraction” and “phosphate—exchangeable fraction” from “residue fraction”. These results showed that the forms of heavy metals in the samples, in which existed as sulfide minerals, changed to diffluent forms caused by weathering. These suggested that, for the geological surveying, it must be considered that leaching properties of heavy metals change by weathering state and preservation of samples.
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