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Volume 47 (2006 - 200･･･
- Issue 6 Pages 323-
- Issue 5 Pages 252-
- Issue 4 Pages 188-
- Issue 3 Pages 120-
- Issue 2 Pages 68-
- Issue 1 Pages 2-
Volume 47, Issue 2
Displaying 1-4 of 4 articles from this issue
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Masako TERAMOTO, Jun SHIMADA, Takanori KUNIMARU2006 Volume 47 Issue 2 Pages 68-76
Published: June 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSTo interpret the groundwater regime in impermeable rocks, stable isotopic analyses have been done on pore waters collected from the abstraction of the drilled cores. The stable Oxygen and Hydrogen isotopes and EC data show that the origin of porewaters in the study area would be divided into three groups; present precipitation, paleo precipitation and fossil seawater.
The effecting depth of paleo precipitation is about 400m below the sea level, while present precipitation is infiltrated only down to 160m. It is considered that the difference of the sea level between glacial and inter glacial period caused the diversity of groundwater activities.View full abstractDownload PDF (2243K) -
Yukinobu YOSHIDA, Mikiya ANDO, Wataru AKAGI, Daisuke KANBARA, Eiji TAM ...2006 Volume 47 Issue 2 Pages 77-87
Published: June 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThis paper describes a rock mass characterization of the Izumi Group for the tunnel construction of the expressway in the Shikoku region. The Izumi Group is mainly composed of interbeded sandstone and shale of Late Cretaceous in age. The tunnel grounds in the Izumi Group are geologically classified into the four types judging from the geological history of both rock mass slide and hydrothermal alteration. This classification is confirmed by the conversion data during tunneling. The first N-type of tunnel was constructed in undisturbed interbedded sandstones and shales. The second S-type was constructed in rock mass slides. The third H-type was constructed in hydrothermally alterated rock masses. The fourth HS-type was constructed in the ground with the complex history of both the rock mass slide and the hydrothermal alteration. Those four types of tunnel show distinct characteristics of conversion during tunneling respectively. Especially, it is clear that the large displacement tends to appear in H-type and HS-type tunnel ground. The X-ray diffraction analysis suggests that the smectite bearing clay veins originated from hydrothermal alteration have caused a large conversion during tunneling. Therefore, it is very important to confirm the presence of the swelling clay mineral (smectite etc.) before and during tunnel construction.View full abstractDownload PDF (2468K) -
On the Effects of Signal Cable Insertion to Measurement Circuit and Grouping of the SensorsMasuyuki UJIHIRA, Kenji OHARA, Fumito ITO, DAUREN Akhmetov, Toyoharu N ...2006 Volume 47 Issue 2 Pages 88-97
Published: June 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSSteel wire cable sensor (SWCS) stretched along a rock slope is effective to detect the sign of a big scale rock fall and slope failure, because the sensor could detect the collision vibrations of rock particles and blocks that appear preceded the big failure. In the conventional SWCS system, electric signals generated in SWCS are once amplified by amplifiers placed on the slope and are transmitted to the room for measurement. It is considered that practical applicability will be increased if the signals could be transmitted directly from SWCS to measurement house without amplifying on the slope, because the accidents of measurement circuit occurs mainly around the amplifiers placed on the slope. Moreover, practical applicability will be increased economically, if the number of channels of measurement instrument is decreased, grouping of plural strings of SWCS. In this study, it was examined how much length of coaxial signal transmission cable could be inserted between SWCS and amplifier in the measurement house without losing the signal characteristics. Then it was confirmed theoretically and experimentally if the output level of signal of SWCS was kept for practical use, when 4-13 strings of SWCS were grouped in parallel or in series to a channel. Results obtained from these examinations are as follows:
1) Length of coaxial signal transmission cable which could be inserted between SWCS and measurement house without pre-amplifying on the slope surface is 120m; 2) According to the field tests, rock fall behaviors could be interpreted clearly from the changes of signal waveforms, even when the coaxial signal transmission cable was inserted between SWCS and amplifier placed in the measurement house; 3) Rock fall characteristics could be identified, when the 4-13 strings of SWCS are grouped both in parallel and in series to a channel in addition to the insertion of coaxial signal transmission cable.View full abstractDownload PDF (3083K) -
A Case Study of Application for Practical Rock Fall at Hikata-Domari Rock Shed in HokkaidoShogo HOSOYA, Masuyuki UJIHIRA, Naoshi MIYASHITA, Yasuyuki IKEDA, Shin ...2006 Volume 47 Issue 2 Pages 98-109
Published: June 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSAuthors have been studying on 3-dimensional rock fall simulation method to evaluate rock fall behaviors such as falling velocity, trajectory, jumping height, horizontal spread and traveled distance, preceded the construction works of rock fall protection structures. In this paper, taking up the rock fall which practically occurred at Hikata-domari Rock Shed in Hokkaido, distribution of practical rock fall points and the distribution that was calculated using 3-d simulation program were compared. From these observational and numerical studies, following points were made clear: 1) Values of calculated traveled distance and jumping height of fallen blocks were a little larger than those practically observed, when the conventional calculation conditions that were estimated using the slope conditions of a quarry were applied. It was considered that the gap between observation and calculation should have appeared due to the existence of steps or talus composed of soil, gravels and rocks. 2) Reasonable distributions of rock fall points and jumping height could be calculated, by adjusting only the viscosity coefficient. It can be said that calculation conditions related with stiffness and viscous damping constant settled newly in this study will be applied to the rock slopes of similar conditions.View full abstractDownload PDF (1953K)
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