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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Engineering Geology
Journal Basic Information
Journal DOI :
The Korea Society of Engineering Gelolgy
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Volume & Issues
Volume 18, Issue 4 - Dec 2008
Volume 18, Issue 3 - Sep 2008
Volume 18, Issue 2 - Jun 2008
Volume 18, Issue 1 - Mar 2008
Selecting the target year
Characterization of Physical Factor of Unsaturated Ground Deformation induced by Rainfall
Kim, Man-Il ; Jeon, Gyo-Cheol ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 127~136
Geophysical survey for establishing a wide site for the distribution of water content, wetting front infiltration due to the rainfall, and distribution of groundwater level has been performed by using 8round penetration radar (GPR) method, electrical resistivity method, and so on. On the other hand, a narrow area survey was performed to use a permittivity method such as time domain reflectometry, frequency domain reflectometry, and amplitude domain reflectometry methods for estimating volumetric water content, soil density, and concentration of contaminant in surface and subsurface. The permittivity methods establish more corrective physical parameters than different found survey technologies mentioned above. In this study for establishment of infiltration behaviors for wetting front in the unsaturated soil caused by an artificial rainfall, soil physical parameters for volumetric water content, pore water pressure, and pore air pressure were measured by FDR measurement device and pore water pressure meter which are installed in the unsaturated weathered granite soil with different depths. Consequently, the authors were proposed to a new establishment method for analyzing the variations of volumetric water content and wetting front infiltration from the responses of infiltrating pore water in the unsaturated soil.
An Experimental Study on Density Log Correction for Plastic Cased Slim Boreholes
Lee, Seung-Jin ; Kim, Yeong-Hwa ; Hwang, Byoung-Chol ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 137~144
The stand-off errors due to the different separations between the sonde and the borehole wall were measured and analyzed in 4 physical borehole models located in Kangwon National University having different densities with cylindrical and half cylindrical PVC and/or acrylic casings. The analysis of the stand-off error data based on the "spine and ribs" technique suggests a well defined rib line for each model irrespectively of the types and thicknesses of the casing, and that the gradients of the ribs are proportional to the densities of the models. By using these characteristics successful density correction could be made for the plastic casings in NX sized boreholes.
The Widening of Fault Gouge Zone: An Example from Yangbuk-myeon, Gyeongju city, Korea
Chang, Tae-Woo ; Jang, Yun-Deuk ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 145~152
A fault gouge zone which is about 25cm thick crops out along a small valley in Yangbuk-myeon, Gyeongju city. It is divided into greenish brown gouge and bluish gray gouge by color. Under the microscope, the gouges have a lot of porphyroclasts composed of old gouge fragments, quartz, feldspar and iron minerals. Clay minerals are abundant in matrix, defining strikingly P foliation by preferred orientation. Microstructural differences between bluish pay gouge and greenish brown gouge are as follows: greenish brown gouge compared to bluish gray gouge is (1) rich in clay minerals, (2) small in size and number of porphyroclasts, and (3) plentiful in iron minerals which are mostly hematites, while chiefly pyrites in bluish gray gouge. Hematites are considered to be altered from pyrites in the early-formed greenish brown gouge under the influence of hydrothermal fluids accompanied during the formation of bluish gray gouge that also precipitated pyrites. It is believed that the fault core including bluish gray gouge zone and greenish brown gouge zone was formed by progressive cataclastic flow. In the first stage the fault core initiates from damage zone of early faulting. In the second stage damage zone actively transforms into breccia zone by repeated fracturing. The third stage includes greenish brown (old) gouge formation in the center of the fault core mainly by particle grinding. In the third stage further deformation leads to the formation of new (bluish gray) gouge zone while old gouge zone undergoes strain hardening. Consequently, the whole gouge zone in the core widens.
Investigation on the Credibility of the Vibrating Wire Strain Gauges used for the Tunnel Instrumentation
Kim, Hak-Joon ; Park, Chan ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 153~158
Vibrating-wire strain gauges are widely used for the tunnel instrumentation because of the long-term stability at humid environments. Domestic strain gauges are mainly used in Korea due to the high cost of the foreign strain gauges. The credibility of the domestic strain gauges is not properly proven even though strain gauges produced by many different companies are available in the markets. The purpose of this paper is to investigate the credibility of the 2.5" strain gauges by using a laboratory compression test.
Consideration of Changed Attitude of Discontinuity through the Depth -Example at Honam Coal Field and Around Suwon Area-
Lee, Byung-Joo ; Choon, Sun-Woo ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 159~166
We have a question about the changing possibility of orientation of discontinuities through the depth of under-ground. To know this, the data from Honam coalfield composed of shale, sandstone and coal and Suwon area which crops out mica schist, were analyzed the discontinuities measured by BIPS and Televiewer. In Honam coalfield the orientations of joints are changed at 30-40 m depth of underground and in Suwon area they are changed around 20 m depth. To compared the results from Honanam coalfield and Suwon area, there are different rock type and geologic structure. However, the attitude of the discontinuities are changing at 20-30 m depth of underground.
The Variation Characteristics of Groundwater Level with Distance from Shoreline in the Jeju Island
Kang, Dong-Hwan ; Yang, Sung-Il ; Kim, Tae-Yeong ; Park, Hyun-Joo ; Kwon, Byung-Hyuk ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 167~176
The variation characteristics of groundwater level with distance from shoreline at Jeju Island was investigated using groundwater level data monitored from 257 wells for dry season (December 1998) and wet season (July 1997), respectively. Groundwater levels of the dry season were
with an average of 60.49 m, while those of the wet season were
with an average of 57.66 m. Groundwater level of the dry season was higher than that of the wet season, which was caused by heavy rains between June and October, 1998 at the Jeju Island. Correlation coefficients between altitude and groundwater level for dry and wet seasons were above 0.86, and those between dry season and wet season groundwater levels were very high above 0.95. 257 groundwater level data were classified at an interval of 500 m. Average values for altitude, groundwater levels and distance from shoreline were calculated for 17 intervals. Altitude and groundwater level fur dry and wet seasons at
intervals were increased with distance from shoreline, but those at
intervals were irregularity. Linear functions of the groundwater level for dry and wet seasons as distance from shoreline were estimated, and the coefficient of determinant at
interval data was higher than it at
interval data. Increasing rate of groundwater level at
intervals was more 2 times than it at
intervals. This results are caused by linear increase of groundwater level to 4 km from shoreline and by irregularity of groundwater level at the
3-D Slope Stability Analysis on Influence of Groundwater Level Changes in Oksan Landslide Area
Seo, Yong-Seok ; Kim, Sung-Kwon ; Lee, Kyoung-Mi ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 177~183
In the study, we carried out a 3-D analysis to assess the influence of groundwater level changes on the slope stability, conducting a series of back-numerical analysis to delineate the critical line of the shear strength of the failure surface of a landslide, and a laboratory test to determine the geo-mechanical properties of soil samples. The analysis result shows that the shear strength determined by the laboratory test was distributed below the critical line of shear strength estimated by back-analysis. Differences between driving and resisting force were also analyzed in groundwater conditions of dry and saturation. It appeared that the stress gets greater towards the slope center of the landslide, and the debris mass moves downwards. According to the analysis, the factor of safety becomes 1 with the rise of foundwater level up to -0.85 m from the slope surface, while the slope tends to stay stable during dry seasons.
The Analysis of Geothermal Gradient at Icheon Hot Spa Area
Lee, Chol-Woo ; Moon, Sang-Ho ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 185~190
Nine wells have been developed for uses of thermal waters at the Icheon hot spa area. Drilling depths of those hot spring wells range from 166 to 294 m and their piezometric heads are located at about 50 m below the surface. Using the differences between the surface and bottom temperatures within all boreholes, we can simply estimate geothermal gradient in this area. Thus, we obtained the highest, lowest and average gradient values as
from SB-2 well,
from SB-1 well and approximately
, respectively. However, observing the MRD-2 well additionally drilled into the depth of 996 m, we found out that this study area has widely experienced the temperature disturbance due to thermal groundwater penetration through the fracture systems within the depth of 720 m. Unlikely this phenomenon, we can conclude that the groundwater flow below the depth of 720 m does not exist. Therefore, using only those temperature data below the 720 m depth, we can estimate reasonable geo-thermal gradient values as
in this study area. Pumping test shows that outflowing temperature is
corresponding to the temperature logging data at 720 m depth.
A Case Study on Analysis of Landslide Potential and Triggering Time at Inje Area using a RTI Warning Model
Chae, Byung-Gon ; Liu, Ko-Fei ; Cho, Yang-Chan ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 191~196
This study is a case study for application of the RTI warning model to Korea which was previously developed to predict landslide potential and occurrence time during a rainfall event. The rainfall triggering index (RTI) is defined as the product of the rainfall intensity I (mm/hr) and the effective accumulated rainfall
(mm). This index is used to evaluate the landslide and debris-flow occurrence potential at time t during a rainfall event. The upper critical value (
) of RTI and the lower critical value (
) of RTI can be determined by historical rainfall data of a certain area. When the rainfall intensity exceeds the upper critical value, there are high potential to occur land-slides. The analysis result can predict landslide occurrence time of an area during a rainfall event as well as land-slide potential. The result can also be used as an important data to issue early-warning of landslides. In order to apply the RTI warning model to Korea this study analyzed rainfall data and landslides data in Inje county, Gangwon province, Korea from July 13 to July 19, 2006. According to the analysis result, the rainfall intensity exceeded the upper critical value 23 hours ago, 11 hours ago, and 9 hours ago from 11:00 in the morning, July 16. Therefore, landslide warnings would be issued three times for people evacuation for avoiding or reducing hurts and dam-ages from landslides in mountainous areas of Inje.
Suggestion of a Modified RMR based on Effect of RMR Parameters on Tunnel Displacement in Sedimentary Rocks
Seo, Yong-Seok ; Yim, Sung-Bin ; Na, Jong-Hwa ; Park, Si-Hyun ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 197~205
Total displacement under non-reinforcement is a quantitative index of rock mass behavior during tunnel excavation and depends widely upon geological characteristics. The primary purpose of this study is to suggest a rock mass evaluation method, well representing tunnel behavior during excavation, according to rock type. A 3-D numerical analysis was carried out, with consideration of the shape of tunnel section, excavation condition and so forth, in a sedimentary rock-based tunnel, and total displacements under non-reinforcement according to rock mass class were calculated. Finally, quantification analysis was carried out to assess correlation of the total displacement with RMR parameters. As the result, a modified RMR system fer quantification of rock mass behavior during tunnel excavation is suggested.
Comparison of Time-Dependent Deformation in Unconsolidated Mudstones with Different Clay Content
Chang, Chan-Dong ; Myoung, Woo-Ho ; Lee, Tae-Jong ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 207~214
We conducted uniaxial consolidation tests in mudstone samples with different clay content, in order to investigate time-dependent deformation and its characteristics. A significant amount of time-dependent strain was observed at a constant stress level immediately after a jump of stress was applied. For a given mudstone, the amount of time-dependent deformation was nearly proportional to the increment of stress, suggesting a linear viscous rheology. The amount of time-dependent strain increases with clay content, implying that clay plays an important role in creep of the unconsolidated mudstone. A power-law model was suitably applied to our results, suggesting that a short-term prediction of time-dependent deformation of the mudstone is tentatively feasible.
Analysis of Influence factors to Compressive and Tensile Strength of Basalt in Cheju Island
Nam, Jung-Man ; Yun, Jung-Mann ; Song, Young-Suk ; Kim, Jun-Ho ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 215~225
In order to investigate the influence factors to compressive and tensile strength of basalt in Cheju Island, rock samples of Pyosenri basalt, trachy-basalt and scoria were taken from Seoguipo-Si Seongsan-Eup area, and a series of uniaxial compressive strength test and Brazilian test were carried out. Especially, these tests were performed in consideration of the loading speed, the moisture content in rock sample, and the anisotropy of rock strength. The uniaxial compressive strength was increased gradually as the loading speed rose. The increasing quantity of uniaxial compressive strength had a difference in each rock types. Also, the strength was decreased with increasing the moisture contents in rock sample by pore water. As the result of test considering the anisotropy of rock strength, the compressive strength in condition of failure occurred parallel to stratified layer is decreased about 12-26% more than that in condition of failure occurred inclined to stratified layer.
Pull-out Resistance Characteristics of the Anchor Bar According to the Grouting Material
Yea, Geu-Guwen ; Song, Young-Suk ;
The Journal of Engineering Geology, volume 18, issue 2, 2008, Pages 227~232
In this study, the pull out resistance characteristics of an anchor bar to support a spillway installed in a slope are investigated by field tests. The injection materials were a cement mortar and cement milk. Unconfined compression strengths of those materials under several conditions were measured. As the result of compression test, the unconfined compression strengths of the cement mortar and the cement milk have positive proportional relation-ship with the water-cement ratio. They also have negative proportional relationship with increasing the curing time. In the same condition of water-cement ratio and curing time, the unconfined compression strength of cement milk is larger than that of cement mortar. In order to reduce the eccentricity in anchor bar during pull-out test in the field, the installation apparatus was improved by inserting a nut type of steel fixing coupling into the anchor bar. As the result of the pull-out test, the strength modification of cement milk was increased steeply at the early curing time. However, that of cement mortar was increased gradually with passing the curing time. Therefore, the cement milk has to use as the injection material for a prompt construction of anchor bar because the strength modification of cement milk is occurred at the early curing time.