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Volume 45 (2004 - 200･･･
- Issue 6 Pages 281-
- Issue 5 Pages 224-
- Issue 4 Pages 174-
- Issue 3 Pages 118-
- Issue 2 Pages 60-
- Issue 1 Pages 2-
Volume 45, Issue 6
Displaying 1-5 of 5 articles from this issue
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Gen FURUYA, Naoki WATANABE, Takeshi KOMATSUBARA, Osamu SATO, Hideaki M ...2005 Volume 45 Issue 6 Pages 281-290
Published: February 10, 2005
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSNa-Cl type groundwaters of high concentration have been often found at landslides in the Higashi-kubiki area, including the Utsunomata landslide, in Niigata Prefecture, Japan. The well loggings were carried out to profile the electric conductivity of groundwater in the landslide mass, and simultaneously groundwater samples were collected for the chemical analysis and the determination of oxygen isotopic ratio. The groundwater profiles in the active landslide mass showed the drastic increase of the electric conductivity around the depth of sliding surface. Such a feature is similar to the chemocline. On the other hand, in the inactive landslide mass, no significant variation was recognized in the profile. Groundwater collected from shallow to deep layer in the landslide mass were chemically classified into following four types in descending order: (1) Ca-HCO3 and Na, Ca-HCO3, (2) Na-SO4, (3) Na-HCO3, and (4) Na-Cl. Considering the relationship between the oxygen isotope ratio and chloride concentration, Na-Cl type groundwater were formed by the mixing the meteoric water with the altered fossil seawater that underwent a similar diagenesis to the the Nishiyama formation. These groundwater suggest that the deep fossil seawater as an abnormally pressured hydrothermal fluid ascend through the fault fractures and inject the landslide mass.View full abstractDownload PDF (1891K) -
Satoshi NISHIYAMA, Yuzo OHNISHI, Takao YANO, Manabu TAKAHASHI, Shuhei ...2005 Volume 45 Issue 6 Pages 291-303
Published: February 10, 2005
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSFor the purpose of understanding the hydraulic behaviours of rock joints undergoing shear deformations, the shearflow coupling experiments were performed. The results indicated that the macrosopic permeable characteristics are greatly affected by the microscopic structures of joint surface, and the cubic law, which is popularly used for permeability characteristics evaluation, cannot be applied where the mechanical aperture width is small in the early stage of shearing. In order to evaluate the relationship between fluid flow phenomena and aperture distribution in a rock joint, the numerical analysis based on Lattice Gas Automaton (LGA) was applied to simulate complicated microscopic flows produced by the complex boundary conditions. It was possible by the simulation method to explain the hydraulic behaviours in shear-flow coupling experiments by fluid-wall boundary interaction when water flows through a rock joint.View full abstractDownload PDF (2673K) -
Shiho ASANO, Sumio MATSUURA, Takashi OKAMOTO2005 Volume 45 Issue 6 Pages 304-315
Published: February 10, 2005
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSIt is important to clarify the characteristics of groundwater, which may induce landslides, in order to plan the prevention of landslides, and also to clarify the three-dimensional characteristics of groundwater for large-scale landslides. In this study, for a large-scale landslide area located in a snowy region, we investigated the fluctuations of threedimensional groundwater during the snowmelt period by field observation and numerical analysis. The investigation focused on the thick pyroclastic flow deposit layer that had accumulated in the surface layer. It is considered that this layer plays an important role in transmitting groundwater pressure to the deep slip surface. The following results were obtained. The groundwater level of the landslide area increases as meltwater increases during the snowmelt period, and the magnitude of the rise in water level and groundwater flow direction of each point in the landslide are different. Groundwater tends to be stored in the caved-in part of the upper part of the landslide slope. These characteristics were estimated based on the topography and geological stratum shape. Furthermore, groundwater drainage for preventing landslides was examined using an analytical model. It was shown that draw-down by groundwater drainage affected the depth of drainage and flux of groundwater.View full abstractDownload PDF (4398K) -
Hiroshi KOSAKA, Jun SHIMADA, Katsuhiro HAMA, Takahiro HANAMURO2005 Volume 45 Issue 6 Pages 316-323
Published: February 10, 2005
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSIn order to understand the porewater movement around the drift wall associated with drift excavation, the porewater from drilling core was extracted to measure the electric conductivity and the stable isotopes in Tertiary sedimentary rock mass distributes in Tono mine, Japan.
The result shows as follows;
1) The porewater near the dirt wall was thought to be much influenced by the evaporation associated with drift excavation.
2) The porewater strongly bonded around the rock particle was thought to be less influenced by the evaporation associated with drift excavation.
3) These porewater movement characteristics show distinct differences depend on the lithology around the drift.
4) The difference of the porewater movement characteristics around the drift for the different lithology has also been shown by the groundwater flow characteristics around the drift estimated by the two-dimensional saturated groundwater flow simulation.
The methods applied in this study was confirmed to be very effective to understand the groundwater movement around the drift associated with drift excavation, especially to understand the development of the unsaturated zone around the drift.View full abstractDownload PDF (1770K) -
Kenji DAITO, Yuichi KANEWAKI, Yasuhiro MATUDA, Shigeo SAEKI2005 Volume 45 Issue 6 Pages 324-331
Published: February 10, 2005
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSIn this thesis, the case where both unconfined groundwater in surface layer and confined groundwater in deep layer are influenced by underground wall constructed along with excavated structure is assumed, and the ideal way of preservation measures of groundwater flow in such a excavated structure is mentioned.
In this research, the multilayer ground was modeled by three-dimensional finite element method, and connecting pipe as preservation measures of groundwater flow was overlapped with three-dimensional ground model. Moreover, The underground wall was modeled and built in three-dimensional ground model. And, the authors analyzed the influence on groundwater condition by changing the relation between depth of underground wall and depth of clay layer, permeability of clay layer, installation location and passing water ability of connecting pipe. When presumed depth and permeability of clay layer are different from actual ones, it is understood that there is little effect of preservation measures of groundwater flow from an analytical result.View full abstractDownload PDF (2329K)
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