All issues
Volume 42 (2001 - 200･･･
- Issue 6 Pages 335-
- Issue 5 Pages 264-
- Issue 4 Pages 208-
- Issue 3 Pages 140-
- Issue 2 Pages 74-
- Issue 1 Pages 2-
Volume 42, Issue 5
Displaying 1-7 of 7 articles from this issue
- |<
- <
- 1
- >
- >|
-
Masaaki KOMAZAKI, Kenji URATA, Fumito ITO, Masuyuki UJIHIRA, Tetsuaki ...2001 Volume 42 Issue 5 Pages 264-273
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe authors have been studying a cable sensor based monitoring system for rock fall detection. The tensile strength of cable sensor (CS) is low and not sufficient for usage under real environment conditions. For this reason, steel wire type cable sensor (SWCS) is proposed with the cable sensor coaxially rolled in steel wire. Here, results of a field test, with SWCS installed on a slope, are presented and the following points are made clear.
1). An accelerometer was installed on SWCS, and experiment on sensitivity analysis was performed in which the sensors were excited by blowing their neighborhood. It was shown that there was an exponential dependence between the output voltage of the SWCS and the accelerometer output. The derived equation is possible to transform the output signal of the SWCS into the output signal of the accelerometer, and the sensitivity difference of the sensors could be eliminated. 2). The desired output voltage of SWCS, installed in a grid pattern on a real slope, was gained after amplification with rate of 2. There is a time lag between output voltage waveform of different channels caused by the rock dropped from the upper point of the slope. The analysis of the time lag and the output waveform provides the possibility of the fallen rock behavior monitoring, including jumps, crashes, tracking. The visual pattern of the fallen rock behavior is reconstructed using topographical representation. 3). The analysis of the curve, connecting the initial points of the SWCS output waveforms, provides an information about falling process parameters (velocity coefficient, friction coefficient, the rock fall velocity at the slope foot, kinematical energy). These parameters are valid for design of protective constructions. Also, the SWCS, being used for the long-term monitoring, can be of practical use for large-scale rock fall prediction by measurement of the current frequency of the small rock falls.View full abstractDownload PDF (3668K) -
Shigenobu HIRAIDE, Koichi SUZUKI, Makiko WATANABE, Wataru MORISHIMA, M ...2001 Volume 42 Issue 5 Pages 274-285
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSVolcanic mudflow (Lahar) deposits, generated after the voluminous 1991 Mt. Pinatubo eruption, have caused disastrous damage in the Mt. Pinatubo area, including changes to the groundwater resources. Such changes prevented the recovery of agriculture. Consequently, we have applied an electrical survey to investigate groundwater in the disastrous area along Bamban and Pasig-Potrero river. Laboratory experiments were carried out to reveal the electric characteristics of the Lahar deposits and the former buried landsurface. We showed a relationship between water-saturation and sediment resistivity and estimated the resistivity of aquifers. Chemical analyses of groundwater showed thet groundwater with low resistivity contains high concentration of SO42- ions, especially in shallow layers of the Lahar sediments. The resistivity profiles indicate that the high resistivity zone corresponds to partially saturated sediments, and the low resistivity zone, underlying the high resistivity zone, to aquifers. Our study has demonstrated that groundwater depth and water quality in this area can be estimated using electical survey methods.View full abstractDownload PDF (5856K) -
Minoru YAMANAKA, Keinosuke GOTOH2001 Volume 42 Issue 5 Pages 286-293
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe eruption activities of Unzen Volcano located at Nagasaki Prefecture had produced huge amount of deposits by frequent occurrence of pyroclastic flows. This volcanic deposits remained at the foot of mountain has much risk of a debris flow along the basin. In order to utilize the volcanic deposits as a construction material, the compressive and static shear properties tests with will be effected by submergence, and more the dynamic tri-axial tests and so on were carefully carried out in the laboratory.
As a result of this study, it was concluded that 1) the high bearing capacity is expected because of the high internal friction angle of this volcanic deposits, 2) it is necessary to compact sufficiently because the fall of strength parameter and the increase of compressive strain will occur by a submergence, 3) liquefaction resistance is high value comparing with the Toyoura standard sand. And it is cleared that the volcanic deposits is a useful material as a fill, a subgrade material and a foundation ground.View full abstractDownload PDF (2226K) -
Tetsuro HIRONO, Manabu TAKAHASHI, Satoru NAKASHIMA, Ken IKEHARA2001 Volume 42 Issue 5 Pages 294-299
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSWe applied the X-ray CT images of fluid advection in laboratory permeameter, which is made from acrylic plastics with low absorption of X-ray, in order to visualize the advecting fluid image during permeability testing and to elucidate the relationship between fluid flow property within fault-related rocks and their deformation mechanism. As a result, X-ray CT image can produce high resolution and three-dimensional fluid flow distribution was measured for fault-related rocks. The fault zones of independent particulate flow mechanism play a role as conduit to fluid flow while cataclastic fault zones act as barriers The localized permeabilities along permeable fault zones, calculated by fluid front rates, are approximately one-orders higher than averaged bulk permeability derived from the pressure or volume difference betweeninflow and outflow in permeameter.View full abstractDownload PDF (3829K) -
Takayuki MATSUMOTO2001 Volume 42 Issue 5 Pages 300-307
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe geological survey of surface and boring survey was carried out to build a bridge on the fault sheared zone, and was estimated as a result of investigation. A support layer could be confirmed by the boring survey, and it was judged that bridge construction was possible. This fault sheared zone belongs to the Median Tectonic Line Active Fault system which is one of the most highly active fault in Japan. But, the main active fault locates 0.5 to lkm north of the planning point. And investigated fault sheared zone has not been so active since the late Pleistocene. Therefore, I proposed it when it could cope with it by holding earthquake-proof design based on active fault presumed in the neighborhood of the investigation area.View full abstractDownload PDF (2828K) -
Yukinori MATSUKURA2001 Volume 42 Issue 5 Pages 308-313
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSDownload PDF (1629K) -
Hideki INAGAKI2001 Volume 42 Issue 5 Pages 314-318
Published: December 10, 2001
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSDownload PDF (1007K)
- |<
- <
- 1
- >
- >|