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Volume 47, Issue 1
Displaying 1-5 of 5 articles from this issue
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Satoru KAWASAKI, Akira MURAO, Naoki HIROYOSHI, Masami TSUNEKAWA, Katsu ...2006 Volume 47 Issue 1 Pages 2-12
Published: April 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSNatural soil contains approximately 107 to 109 microorganisms per gram. Considering this large number of microorganisms, it is expected that soil and rock engineering, especially the field of mechanics, may be able to develop a novel eco-friendly technology to improve the sealability of soil and rock. We performed fundamental laboratory tests in order to develop a novel conceptual grout, hereafter denoted as biogrout. Biogrout consists primarily of calcium carbonate, one of the typical cement elements in soil and rock. This compound can fill the voids and cracks in soil and rock using microbial metabolism. We performed separation tests on calcium carbonate in test tubes, examining the effects of several test conditions, including temperature, organic nutrition, and different buffering conditions, on the separation of calcium carbonate when challenged with commercially available dry yeast and microorganisms naturally living in soil. Furthermore, we examined the improvements in the sealability of sand and clay following biogrout improvement, confirming that coefficients of permeability of both soil types decreased by approximately one order of magnitude from those seen for normal soils. Although a number of problems will need to be addressed, these test results indicate that biogrout is a promising candidate to improve ground properties. The development of such a compound has been successful using microbial metabolism.View full abstractDownload PDF (2008K) -
Daigo MARUYAMA, Satoru KOJIMA, Tomoyuki OHTANI2006 Volume 47 Issue 1 Pages 13-22
Published: April 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSOrientation, filling minerals and surface morphology of fractures observed in the integrated data of boring cores and borehole TV images of Late Cretaceous Toki granite in central Japan were analyzed at the interval between 51-1, 012m of vertical hole drilled in Toki City, Gifu Prefecture. Orientation of the fractures are grouped into NNW, NS and NE-ENE trends with steep-dips and horizontal attitude. The steeply dipping fractures change their strikes from NNW to NNE and ENE to EW with depth. Fracture surface morphologies are classified into the planar type with rough surface (Pr), with flat surface (Pf), with striations (Ps), and irregular type with rough surface (Wr). The Ps fractures trending NNW-SSE and dipping steeply at the depth about 340m were formed by the horizontal shear. Most of the Pr, Pf and Ps fractures are dipping steeply, and are considered to form as shear fractures on the basis of their morphologies. Part of the horizontal Wr fractures observed near the unconformity with the overlying Cenozoic formation are interpreted as sheeting joints, whereas the steeply dipping Wr and rest of the horizontal Wr seem to be cooling joints. The filling minerals include clay minerals, chlorite, epidote, quartz and calcite.View full abstractDownload PDF (1860K) -
Bunji TAKANASHI2006 Volume 47 Issue 1 Pages 23-26
Published: April 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThis study is intended as an investigation of differences in the consolidation yielding stress of Kanto loam under the two conditions, submerged and unsubmerged. The examination results under the both conditions indicated that in 76% of the whole samples, the stress value obtained from unsubmerged samples is 1.O to 1.2 times as high as submerged samples; and in the remaining 24%, the stress value of unsubmerged samples is 1.3 to 1.7 times as high as submerged samples. It was also discovered in the above-mentioned data that there is a relatively strong correlation between these two factors (the consolidation yielding stress of unsubmerged samples and of submerged samples); therefore, it may be possible to obtain the estimated stress value of either sample from the value of the other.
If the consolidation yielding stress value under the unsubmerged condition can be utilized to prevent ground subsidence at the site composed of Kanto loam, it should allow more economical design and planning than when the submerged condition is utilized. From this viewpoint, it is significant to study the mechanism under the unsubmerged condition that creates greater consolidation yielding stress than the submerged condition.View full abstractDownload PDF (764K) -
Hiroshi OSHIMA, Akira MURAO2006 Volume 47 Issue 1 Pages 27-38
Published: April 10, 2006
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESS -
Hiroyuki OHNO, Akira MURAO2006 Volume 47 Issue 1 Pages 40-49
Published: April 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe environment of the earth has always kept changing for 45.6 hundred million years. Then, there is a possibility that the human race cannot live in the case that the environment on the earth change rapidly. We want to avoid an artificial change of environment, so we are working on the environmental problems. Such environmental problems are the same as food and energy problem.
Geological engineers have made efforts to the making technology and the disaster prevention, but it had not made efforts to the environmental problem. Considering the earth history, the author discusses the character of engineering geology. As the results, the geological engineers must have several professional skill, and have correct engineer ethics. In addition, we must examine the problem from near-field to far-field, and at short-term to long-term. That is, the geological engineer has to become the human who have sense of four-dimension. Then, we should make the education system and quality control system. Finally, onto the most important, we need to also train on the job.View full abstractDownload PDF (2185K)
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