All issues
Volume 39 (1998 - 199･･･
- Issue 6 Pages 486-
- Issue 5 Pages 414-
- Issue 4 Pages 346-
- Issue 3 Pages 244-
- Issue 2 Pages 174-
- Issue 1 Pages 4-
Volume 39, Issue 4
Displaying 1-7 of 7 articles from this issue
- |<
- <
- 1
- >
- >|
-
Kaname TAJIRI, Hiroshi NAKAYAMA, Syojiro ARAMAKI, Wakatsu FURUSAWA, Sh ...1998 Volume 39 Issue 4 Pages 346-351
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSDue to the presence of adjacent Median Tectonic Line and Mt. Aso, geo-tectonics of Kumamoto and surrounding areas are quite complicated. Although past studies have considered only partial geo-tectonics or individual faults in this area, it is recommended to apply three dimensional representations of wide area geo-technical information for a clearer understanding. As a results, geo-technical characteristics and distribution patterns were analyzed for Togawa-lava of aquifer which is the ground water resource in Kumamoto City. Also, from the distributions of pyroclastic flow sediments Aso-3 and Aso-4 in Mt. Aso, which carries artesian water of Togawa-lava, ground water flow mechanism has been studied for Kamiezuko-Lake (Suizenji). Further, thickness patterns were also investigated for terrace gravel, which is popularly used as foundation material in buildings.View full abstractDownload PDF (2769K) -
Taketomi SUMI1998 Volume 39 Issue 4 Pages 352-360
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSIn general, the grain size analysis of conglomerate and gravel bed distributed deep underground are carried out with rock sections or boring cores. It is possible to obtain the apparent grain size distribution with these methods, however, and the key is skillfully estimate the original grain size distribution from the apparent grain size distribution.
In this paper, a cumulative probability function of apparent grain size is led theoretically in an ideal condition. Using the function, standard curves for estimating the original grain size distribution from the apparent grain size distribution are obtained. It is also evaluated that, the standard curve method is applicable to actual grains.View full abstractDownload PDF (1458K) -
Seiki YAMAUCHI, Akio IWATA1998 Volume 39 Issue 4 Pages 361-371
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe eastern part of the Shinji Lowland, southwest Japan is separated by the Lake Nakaumi into the Matsue Plain on the west and the Yumigahama Peninsula on the east. The Miocene sediment which distributes in and around the Lowland is more than 1000m thick and forms a large syncline in the Lowland. Geothermal potential in the Lowland is discussed based on geological descriptions of six boreholes which reach to more than 1000m deep and results of gravity and resistivity sounding measurements. Hot water of sulphate type, temperature of which is more than 70°C exists in the fractures about 1300m deep and is sealed by mud stone about 600m thick in the Matsue Plain. On the other side, hot water of common salt type, temperature of which is about 40°C exists in beds of sandstone alternated with mudstone beds in depth of about 1200m. It is concluded that hot water of more than 70°C and 300l/min can be gotten in depth of about 1300m under the Matsue Plain, and water of about 40°C and more than 1000l/min in depth of 1500m under the Yumigahama Peninsula, but water temperature may rapidly increase in depth of more than 1500m.View full abstractDownload PDF (1895K) -
Saiichi SAKAJO, Masao HAYASHI, Takeshi KAMEI, Jin-Chun CHAI1998 Volume 39 Issue 4 Pages 372-379
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe undrained shear behavior of soft rocks consisting of clayey sand and silty clay is simulated by applying an elasto-viscoplastic soil model to the Finite Element Method (FEM). The model parameters are empirically determined based on plasticity index (PI). Comparison with test data shows that the analysis can explain the laboratorymeasured behavior of soft rocks for a wide range of consolidation pressure and for both normally and overconsolidated states. The results indicate that (1) for clayey soft rock, the behavior can be represented by an elasto-viscoplastic model, and (2) the empirical method of determining the model parameters can be used where there is insufficient test information to directly define the model parameters. The computed and the observed undrained shear behavior are discussed by a detailed analysis of stress-strain, excess pore pressure-strain and effective stress paths. The effects of viscid model parameters on the mechanical behavior of the soil model used are also discussed.
A visco-plastic model is used to simulate the undrained behavior of soft rocks sampled from the Sodegaura site near Tokyo. The model parameters are empirically determined from plasticity index (PI). By comparison with test data, it is found that predictions of undrained shear strength differ from the experimental results slightly, but excess pore pressures fit the test data quite well. Generally, the model can explain the behavior of soft rocks for a wide range of consolidation pressure and for both normal and overconsolidated states.
The empirical method of determining the model parameters can be applied to soft rocks. Where insufficient information expects to directly define the model parameters, the empirical relationships between PI and the model parameters can be used.
For the elasto-viscoplastic model used, the viscid model parameters, α and v0, have a significate effect on the performance of the model. Numerical results indicate that under the conditions where volumetric strain rate, v (related to the speed of shearing etc.), is larger than the initial volumetric strain rate, v0 (v>v0), the smaller the v0 and the larger the α value are, the higher the predicted undrained strength will be.View full abstractDownload PDF (1295K) -
Kenta OGAWA, Masuyuki UJIHIRA, Shingo SUZUKI, Shougo HOSOYA, Fumiaki I ...1998 Volume 39 Issue 4 Pages 380-390
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSA theoretical study was carried out to elucidate measurement principle of cable sensor which is usually used for invader inspection, because the sensor has possibility to be used for geological measurement. Basing upon the theory on the contact electrification of materials, it is explained that electrons flow from a material of which work function is comparatively small to the material whose work function is larger than the former, when a material contacts to the other. It was concluded this flow of electrons is the source of signals from cable sensor for vibration detection. Considering electrical components of the circuit for vibration measurement, a differential equation which can give output from the circuit is proposed. From this equation, correct principle of cable sensor can be understood. Fundamental tests were carried out to clarify if the cable sensor had enough characteristics for geological measurement. The cable sensor was judged that the sensor could be used for vibration detection instead of acceleration sensor when high accuracy is not required. Then a laboratory test for source locaton of impact point of a steel ball dropping was carried out, where 12 strings of cable sensors were stretched in a grid pattern on the concrete floor. It was found that cable sensor could be used for two dimensional source location of impact sources. This means that the cable sensor can be applicable for the source location of the points of small failures preceded a big rock fall or for the measurement of resultant impact of fallen rocks against a rock sheds or tunnel entrances.View full abstractDownload PDF (2233K) -
Satoru KAWASAKI, Hiroshi ITO, Kazuhiro KOIZUMI1998 Volume 39 Issue 4 Pages 391-400
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSWhen strength and deformation properties of conglomerate are evaluated by rock tests, scale effect of conglomerate specimens and sample disturbance of core samples come into problems. It is considered that these problems become more important as the depth of core sampling increases. A series of laboratory rock tests using conglomerate obtained from deep underground and artificial conglomerate was therefore carried out, and a consideration on scale effect of conglomerate and an evaluation of sample disturbance by core sampling were performed. As for the scale effect, physical and mechanical properties of the specimens, on which the ratios of D/d (D : Diameter of specimen, d : maximum diameter of gravel) were ranging from about 1 to 10, were investigated using mainly artificial conglomerate. As the results, it was clear that the scale effect on the physical and mechanical properties was small and seemed hardly to exist. On the other hand, as for the evaluation of disturbance, the relations between tangent Young's modulus and shear stress levels obtained from unconfined compression tests were arranged for disturbance patterns of core samples, and moreover, evaluation parameters for disturbance were considered.View full abstractDownload PDF (2586K) -
Tsuyoshi HARAGUCHI, Toshio INOKUCHI, Hiromi MATSUOKA1998 Volume 39 Issue 4 Pages 401-405
Published: October 10, 1998
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSDownload PDF (3763K)
- |<
- <
- 1
- >
- >|