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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geoenvironmental Society
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Journal DOI :
Korean Geo-Environmental Society
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Volume & Issues
Volume 7, Issue 6 - Dec 2006
Volume 7, Issue 5 - Oct 2006
Volume 7, Issue 4 - Aug 2006
Volume 7, Issue 3 - Jun 2006
Volume 7, Issue 2 - Apr 2006
Volume 7, Issue 1 - Feb 2006
Selecting the target year
Stability Analysis of a Slope in Unsaturated Weathered Residual Soil Considering the Rainfall Characteristics
Lee, Kang-Il ; Chang, Yong-Chai ; Kim, Tae-Hoon ; Chung, Youn-In ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 5~14
It has been reported that the failure of a slope in weathered soils or rocks induced by intensive rainfall occurs mainly within 2.0m below the ground surface, and that the effect of rainfall on the rise of the ground water level is not significant if the ground water level inside the slope is not so high before rainfall. Most slopes in Korea, however, have been examined to rather fail at the deeper part since they are usually designed on the basis of assumption that the ground water level rises up to the surface when raining. In this study, the rise of ground water level and slope stability were examined in order to verify the appropriateness of the current ground water level condition that has a significant effect on slope stability using the average daily rainfall in Seoul for the last 30 years. The result showed that the ground water level appears to rise up to 6.0~41.0% of the slope height respectively, and therefore the currently applied condition of ground water level may be somewhat overestimated.
A Study on Prediction of the Coefficient of Horizontal Subgrade Reaction for Pile Using Lateral Pile Loading Test Results
Chun, Byung-Sik ; Seo, Deok-Dong ; Lee, Young-Jae ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 15~24
In this paper, the Coefficient of Subgrade Reaction was analyzed from the data which were the results of lateral pile loading tests and pressuremeter tests on construction sites. The prediction method with N-value was compared with lateral pile loading tests and the results of lateral pile loading tests were compared with the prediction method considering diameter of a pile. Also, the results of lateral pressuremeter tests were compared with those of lateral pile loading tests. As a result, consideration for a diameter and lateral deformation of a pile was needed when the coefficient of horizontal subgrade reaction is presumed. Therefore, a formula which is taking into account the allowable deformation of a pile was suggested from lateral pressuremeter tests in this study.
The Evaluation for Estimation Method of Deformation Modulus of Rock Mass Using RMR System
Chun, Byung-Sik ; Lee, Yong-Jae ; Jung, Sang-Hoon ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 25~32
The deformation modulus of rock masse is a very important design factor for the computation of stability of tunnels and their support systems. Several empirical formulas to estimate the deformation modulus using simple rock classification methods such as RQD or RMR are widely used because field tests to evaluate the deformation modulus are very expensive and time consuming work. However, these formulas can be depended on experiences from the characteristics of local sites in each country. Therefore, in this study, the applicability of empirical formulas was analyzed by comparing estimated value with the measured value from eight sites in South Korea. The results show that the estimated value based on the empirical formulas partially have tendency to overestimate. Especially, in case of sedimentary rocks, it was too difficult to apply to the empirical formulas because there was no relationship between estimated value and measured value. For these reasons, additional data from many tests and accurate analyses are necessary to evaluate the estimation method for the deformation modulus considering the local characteristics of rock masse.
Evaluation of Rock Uniaxial Compressive Strength Using Ultrasonic Velocity
Baek, Seung-Cheol ; Kim, Yong-Tae ; Kim, Hong-Taek ; Yoon, Jun-Sig ; Lee, Yun-Gyu ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 33~42
Eighteen biotite granites on Andong area and twenty seven igneous rocks(diorite, granite, andesite, rhyolite) on Yeosu area were tested to evaluate the correlations between the uniaxial compressive strength values, as determined by the standard uniaxial compression test, and the corresponding results of the ultrasonic velocity. The variability of test results for each test was evaluated by calculating the coefficient of determination or variation. Results indicate that strong correlations exist between the results of uniaxial compression vs the point load, Schmidt hammer and ultrasonic velocity test. The correlation equations for predicting compressive strength using different methods are presented along with their confidence limits. Ultrasonic velocity test used provide reliable estimates of compressive strength.
Study on the Fracture Deformation Characteristics in Rock by Hydraulic Fracturing
Sim, Young-Jong ; Kim, Hong-Taek ; Germanovich, Leonid N. ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 43~53
Hydraulic fracturing is an important and abundant process in both industrial applications and natural environments. The formation of hydraulic fractures includes nucleation, growth, and termination in numerous rock types and stress regimes, at scales ranging from microns to many kilometers. As a result, fracture segmentation, commonly observed at all scales and in all geo-materials, contributes to this complexity in many ways. In particular, the mechanical interaction of fracture segments strongly affect almost all hydraulic fracturing processes. In this paper, the segmented fracture opening deformation in rock by hydraulic fracturing is quantified using boundary collocation method and is compared with non-interacting single fracture.
Case Study Of Reducing Specimen Disturbance Using Vertical Fixing Sample Frame (VFSF)
Lim, Beyong-Seok ; Seo, Deok-Dong ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 55~66
The existing Highway LA-1 of US is required to be replaced for covering increasing regional demands of transportation such as Hurricane evacuation and oil industry. This 28 km crosses wetlands and is a sensitive environmental area. Huge amount of soil investigation and laboratory tests were performed with best efforts to overcome inherit errors of sampling, disturbance, and testing procedures for this project. The data scattering was corrected through using central tendency theory.
Tunneling in Severe Groundwater Inflow Condition
Lee, Young-Nam ; Kim, Dae-Young ;
Journal of the Korean Geoenvironmental Society , volume 7, issue 2, 2006, Pages 67~76
For a hydro power plant project, the headrace tunnel having a finished diameter of 3.3 m was constructed in volcanic rocks with well-developed vertical joint and high groundwater table. The intake facility was located 20.3km upstream of the powerhouse and headrace tunnel of 20km in length and penstock of 440m in height connected the intake and the powerhouse. The typical caldera lake, Lake Toba set the geology at the site the caving of the ground caused tension cracks in the vertical direction to be developed and initial stresses at the ground to be released. High groundwater table(the maximum head of 20bar) in the area of well-connected vertical joints delayed the progress of tunnel excavation severely due to the excessive inflow of groundwater. The excavation of tunnel was made using open-shield type TBM and mucking cars on the rail. High volume of water inflowraised the water level inside tunnel to 70cm, 17% of tunnel diameter (3.9m) and hindered the mucking of spoil under water. To improve the productivity, several adjustments such as modification of TBM and mucking cars and increase in the number of submersible pumps were made forthe excavation of severe water inflow zone. Since the ground condition encountered during excavation turned out to be much worse, it was decided to adopt PC segment lining instead of RC lining. Besides, depending on the conditions of the water inflow, rock mass condition and internal water pressure, one of the invert PC segment lining with in-situ RC lining, RC lining and steel lining was applied to meet the site specific condition. With the adoption of PC segment lining, modification of TBM and other improvement, the excavation of the tunnel under severe groundwater condition was successfully completed.