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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geotechnical Society
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Journal DOI :
Korean Geotechical Society
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Volume & Issues
Volume 28, Issue 12 - Dec 2012
Volume 28, Issue 11 - Nov 2012
Volume 28, Issue 10 - Oct 2012
Volume 28, Issue 9 - Sep 2012
Volume 28, Issue 8 - Aug 2012
Volume 28, Issue 7 - Jul 2012
Volume 28, Issue 6 - Jun 2012
Volume 28, Issue 5 - May 2012
Volume 28, Issue 4 - Apr 2012
Volume 28, Issue 3 - Mar 2012
Volume 28, Issue 2 - Feb 2012
Volume 28, Issue 1 - Jan 2012
Selecting the target year
A Study on the Load Bearing Characteristics Depending on Pile Construction Methods and Pile Load Test Methods Based on Case Analyses
Hong, Seok-Woo ; Choi, Yong-Kyu ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 5~21
DOI : 10.7843/kgs.2012.28.4.5
In our country, in the case of traditional design of pile foundations, only a design depending on end bearing has been performed. However, through the load transfer measurement data that have been carried out for in-situ piles, it was known that skin frictional force was mobilized greatly. In this study, through the analysis of the load transfer test cases of driven steel pipe piles and large-diameter drilled shafts, load bearing aspects of pile foundation depending on pile construction methods and pile load test methods were established. The average sharing ratios of skin frictional force were independent of pile types, pile load test methods, relative pile lengths, pile diameters and soil types. Because the average sharing ratios were over 50%, the case pile foundations mostly behaved as a friction pile and the extremely partial case pile foundation behaved as a combined load bearing pile.
Development of Landslide-Risk Prediction Model thorough Database Construction
Lee, Seung-Woo ; Kim, Gi-Hong ; Yune, Chan-Young ; Ryu, Han-Joong ; Hong, Seong-Jae ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 23~33
DOI : 10.7843/kgs.2012.28.4.23
Recently, landslide disasters caused by severe rain storms and typhoons have been frequently reported. Due to the geomorphologic characteristics of Korea, considerable portion of urban area and infrastructures such as road and railway have been constructed near mountains. These infrastructures may encounter the risk of landslide and debris flow. It is important to evaluate the highly risky locations of landslide and to prepare measures for the protection of landslide in the process of construction planning. In this study, a landslide-risk prediction equation is proposed based on the statistical analysis of 423 landslide data set obtained from field surveys, disaster reports on national road, and digital maps of landslide area. Each dataset includes geomorphologic characteristics, soil properties, rainfall information, forest properties and hazard history. The comparison between the result of proposed equation and actual occurrence of landslide shows 92 percent in the accuracy of classification. Since the input for the equation can be provided within short period and low cost, and the results of equation can be easily incorporated with hazard map, the proposed equation can be effectively utilized in the analysis of landslide-risk for large mountainous area.
Seepage Face and Reliability Indexes of Anisotropic Homogenous Dam at Steady State Condition
Mahmood, Khalid ; Kim, Jin-Man ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 35~42
DOI : 10.7843/kgs.2012.28.4.35
This paper evaluates the effect of anisotropic conductivity on the seepage face and reliability index of an homogeneous dam with and without toe drain. The analysis are conducted under steady state saturated-unsaturated seepage condition using finite element method. Various anisotropic conductivity ratios were interpreted under such conditions as the vertical conductivity is reduced while the horizon conductivity is fixed. The shear strength of soil is defined by the modified Mohr-Coulomb failure criterion. The analysis results demonstrate that the length of seepage face and reliability index at the downstream and upstream of the dam increase with an increasing anisotropic ratio. These results of the seepage face and reliability index, however, depend on the total head difference between the upstream slope and downstream toe. The difference in seepage face and reliability index is attributed to the different equipotential head with different anisotropic ratios of the dam material.
Effect of Curing Temperature on the Strength Characteristics of Lightweight Air-Trapped Soil
Lee, Min-Ah ; Kim, Seong-Won ; Choi, Dae-Kyung ; Park, Lee-Keun ; Kim, Tae-Hyung ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 43~53
DOI : 10.7843/kgs.2012.28.4.43
There are many factors that can cause problems in the application of the lightweight air-trapped soil in the field. Temperature is one of them. However, the effect of temperature on the characteristics of lightweight air-trapped soil has not been studied. Thus, this experimental study is conducted. This study considers three different unit weights of lightweight air-trapped soils, 6, 8, and 10 kN/
which are mostly applied to the field. The lightweight air-trapped soil specimens are cured in the condition of different temperatures based on the characteristic of temperature of Korea. The unconfined compression tests are conducted on the prepared specimens. The settlement behavior of lightweight air-trapped soil on temperature is observed. A photograph is taken using SEM to determine the transformation of air-foams inside the lightweight air-trapped soil on curing temperature. As the results, the effect of curing temperature on the characteristics of lightweight air-trapped soil including compressive strength, settlement, and formation of air-foams is confirmed. Finally, based on this study, the allowable curing temperature of
which can guarantee the quality of lightweight air-trapped soil is proposed.
Installation of Micro-piles Appropriate to Soil Conditions
Hwang, Tae-Hyun ; Mun, Kyeong-Ryeon ; Shin, Yong-Suk ; Kwon, Oh-Yeob ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 55~65
DOI : 10.7843/kgs.2012.28.4.55
This study performs model test to propose the installation method of micro-pile appropriate to various soil conditions such as sand or silt soil. As a result, the crossed installation method (
) of micro-pile is effective in resisting a compression displacement of soil in the case of silt exhibiting the punching shear failure. And the inclined installation method (
) of micro-pile is effective in resisting a lateral displacement of soil in the case of sand to exhibiting the general or local shear failure.
Development of Three-dimensional Approximate Analysis Method for Piled Raft Foundations
Cho, Jae-Yeon ; Jeong, Sang-Seom ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 67~78
DOI : 10.7843/kgs.2012.28.4.67
A three-dimensional approximate computer-based method, YSPR (Yonsei Piled Raft), was developed for analysis of behavior of piled raft foundations. The raft was modeled as a flat shell element having 6 degrees of freedom at each node and the pile was modeled as a beam-column element. The behaviors of pile head and soil were controlled by using
stiffness matrix. To model the non-linear behavior, the soil-structure interaction between soil and pile was modeled by using nonlinear load-transfer curves (t-z, q-z and p-y curves). Comparison with previous model and FEM analysis showed that YSPR gave similar load-displacement behaviors. Comparison with field measurement also indicated that YSPR gave a reasonable result. It was concluded that YSPR could be effectively used in analysis and design of piled raft foundations.
A Study on the Closure Ratio for Tunnel Face Stabilization during Tunnel Excavation in Sand Soil
Kim, Sang-Hwan ; Kim, Ji-Tae ; Lim, Chae-Ho ; Lee, In-Keun ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 79~89
DOI : 10.7843/kgs.2012.28.4.79
This paper presents experimental and numerical studies on the closure ratio of tunnel face to reduce pressure and displacement occurring at tunnel face during tunnel excavation. In experimental study, model tests are carried out according to the closure ratio of tunnel face and tunnel depth. Model test results are analyzed and interpreted by numerical calculation in order to verify results obtained from experimental and numerical studies. It is clearly found that tunnel face stability increases with the increase of the closure ratio of tunnel face. The results also show that tunnel face is stable when the closure ratio of tunnel face is larger than 80%. This research will be very useful to develop the economical tunnel face closing system.
Effect on Matric Suction in Soils due to Hysteretic Soil Water Characteristic Curves
Kim, Jae-Hong ; Hwang, Woong-Ki ; Song, Young-Suk ; Kim, Tae-Hyung ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 91~100
DOI : 10.7843/kgs.2012.28.4.91
Soil-water characteristic curves (SWCCs), which represent a physical property in partially saturated soils, show the relation between volumetric water content and matric suction. The SWCCs exhibit hysteresis during wetting and drying, however experimental expressions used to describe SWCCs have generally ignored the hysteresis. In addition, the shape of SWCC may depend on the void ratio which is changed by soil skeleton deformations or hysteretic behavior under various loading conditions. Hence, it is necessary to understand, both empirically and analytically, the relationship between soil skeleton deformations and the SWCCs of various soils. The typical SWCCs experimentally have drying, wetting, and the second drying curve. The measurement of a complete set of hysteretic curves is severely time-consuming and difficult works, then the first drying curve of SWCC is generally determined to estimate the hydraulic conductivity and shear strength function of partially saturated soils. This paper presents the hydraulic-mechanical behavior of partially saturated soils (weathered soil and silty soil) for volume changes and hysteresis in SWCCs regarding the difference between the first drying and wetting curve.
A Study on the Lining Stability of Old Tunnel Using Groundwater Flow Modelling and Coupled Stress-Pore Water Pressure Analysis
Kim, Bum-Joo ; Jung, Jae-Hoon ; Jang, Yeon-Soo ; Chun, Byung-Sik ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 101~113
DOI : 10.7843/kgs.2012.28.4.101
The degradation of a tunnel drainage system leads to increases in pore water pressure around the tunnel and the lining stress, which results in affecting the tunnel stability. In the present study of the Namsan 3th tunnel, more than 30 year old tunnel, the effects of the drainage performance reduction due to drain hole clogging on the tunnel lining stability were investigated by examining pore water pressure distribution around the tunnel and the lining stresses through numerical analysis. Groundwater flow modeling on the Mt. Namsan region was done first and 3D seepage and coupled stress-pore water pressure finite element analysis were performed on the tunnel using the results of the groundwater flow modeling. The pore water pressure distribution and the tunnel lining stresses could be predicted using a drain hole outflow data measured in the tunnel site. This analysis method may be used to evaluate the current stability of old tunnels for which in most cases field investigations and related information are not readily available.
1g Shaking Table Test on Soil and Stone-column Interaction Behavior under Seismic Loading
Kim, Jin-Man ; Ryu, Jeong-Ho ; Kim, Mi-Na ; Son, Su-Won ;
Journal of the Korean Geotechnical Society, volume 28, issue 4, 2012, Pages 115~124
DOI : 10.7843/kgs.2012.28.4.115
The responses of stone column-improved ground under seismic loading are investigated using a series of 1g shaking table tests. These tests show similar results to those of one dimensional numerical models for stone column-improved ground based on Baez`s assumption on the soil and stone-column interaction. The experimental and numerical results show that the stone column can prevent large shear deformations incurred due to cyclic softening in clayey deposits, but they also show that the surface acceleration in the improved clayey deposits may amplify more than that in unimproved clayey deposits when subjected to short periodic seismic motions.