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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Geotechnical Society
Journal Basic Information
Journal DOI :
Korean Geotechical Society
Editor in Chief :
Seong Wan Park
Volume & Issues
Volume 24, Issue 12 - Dec 2008
Volume 24, Issue 11 - Nov 2008
Volume 24, Issue 10 - Oct 2008
Volume 24, Issue 9 - Sep 2008
Volume 24, Issue 8 - Aug 2008
Volume 24, Issue 7 - Jul 2008
Volume 24, Issue 6 - Jun 2008
Volume 24, Issue 5 - May 2008
Volume 24, Issue 4 - Apr 2008
Volume 24, Issue 3 - Mar 2008
Volume 24, Issue 2 - Feb 2008
Volume 24, Issue 1 - Jan 2008
Selecting the target year
Lateral Movement of Quaywall on Soft Grounds
Hong, Won-Pyo ; Lee, Kwang-Wu ; Cho, Sam-Deok ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 5~16
Field monitoring data of nine sites were investigated to suggest an evaluation method on lateral movement of the quaywall on soft grounds. It was found that in order to evaluate the lateral movement of quaywalls with foundation piles such as the landing pier, the safety factor of slope should be applied with consideration of the stabilizing effect of the piles. If the required safety factor of slope is greater than 1.6 in slope stability analysis with consideration of the stabilizing effect of the piles, the quaywalls are considered to be safe against lateral movement. On the other hand, for the gravity-type quaywalls such as the caisson type quaywall, the required safety factor of slope should be greater than 1.3.
Estimation of Local Scour at Piers Using Artificial Neural Network
Park, Hyun-Il ; Shin, Jong-Hyun ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 17~24
It is known that scour at bridge piers is one of the leading causes of bridge failure. However, the mechanism of flow around a pier structure is so complicated that it is difficult to establish a general empirical model to provide accurate estimation for scour. Especially, each of the proposed empirical formula yields good results for a particular data set but can't show reliable predictability for various scouring data set. In this study, an alternative approach, that is, artificial neural networks (ANN), is proposed to estimate the local scour depth with numerous field data base. The local scour depth was modeled as a function of seven variables; pier shape, pier width, pier length, skew angle, stream velocity, water depth,
. 426 field data were used for the training and testing of ANN model. The predicted results showed that the neural network could provide a better alternative to the empirical equations.
Analysis of Allowable Settlement on Tracks of High Speed Railway
Kim, Young-Ho ; Jeong, Sang-Seom ; Seol, Hoon-Il ; Han, Young-Ah ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 25~34
An application of concrete track is being actively processed for the construction of Korean high speed railway. The concrete track has an advantage in decreasing the maintenance cost, whereas it has much difficulty controlling the long term settlement after settlement occurred. Therefore, the management and control of settlement are very important for the successful construction of concrete track. The purpose of this paper is to verify the allowable settlement between concrete track and ballast track, and piled raft foundation installation effects as settlement reducers for concrete track. Therefore, a series of 3D finite element analyses that take into account the allowable settlement were performed for major parameters such as soil condition, pile installation and loading type. Based on the analysis, it is shown that concrete track causes much smaller settlement than ballast track, and the effect of installation is necessary to effectively reduce the settlement of concrete track.
Evaluation of Stress Distribution Ratio According to Clay Ground Condition and Stone Column Characteristics
Kim, Dong-Eun ; Park, Hyun-Il ; Lee, Seung-Rae ; You, Sang-Ho ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 35~41
Stone columns, one of the soft ground improvement techniques, are being used for not only accelerating consolidation but also increasing bearing capacity of soft grounds. In this study, in order to observe the stress distribution characteristics which are one of the important factors to estimate the settlement reduction of the soft ground, lab-scale experiments were performed in stone column reinforced clay ground. The stress distribution ratio of stone column decreased with the lapse of time after surcharge loading but increased as the stiffness of clay deposit increases. It shows that the modified Baumann and Bauer's solution, which is able to easily predict the stress distribution ratio of stone column reinforced soft ground, exhibits reasonable agreement with the measured data.
A Suggestion of a New Rock Mass Classification System
Kim, Min-Guon ; Lee, Yeong-Saeng ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 43~53
The rock mass classification systems used in Korea are not standardized. And also the criteria values differ between agencies. So different opinions for rock mass classification can occur among engineers who participate in each design process. In this research, a new rock mass classification system was suggested to correct these problems. For this purpose, the criteria used in the Korean agencies were compared with the criteria used in foreign agencies and standard criteria were selected. Thereafter rational and objective criteria values were suggested quantitatively for the new classification system.
Comparison of Safety factor for an Anchored Slope in Accordance with the Effects of Load Transfer
Kim, Sung-Kyu ; Kim, Wak-Kyung ; Park, Jong-Sik ; Joo, Yong-Sun ; Kim, Tae-Hoon ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 55~60
This paper presents how the load transfer mechanism of the ground anchor affects on the stability analysis of anchored slope. The finite element analysis and the conventional limit equilibrium analysis on the anchored slope were performed and compared. The limit equilibrium analysis of the anchored slope is widely used in design practice due to the easiness of the analysis. However, the load transfer mechanism is not considered properly for the analysis. When the failure surface passes through the bonded length of an anchor, the anchor load is disregarded and the factor of safety for the anchored slope is smaller than it should be. In this study, the load transfer distribution was incorporated into the limit equilibrium stability analysis of the anchored slope and the results were compared with those of finite element analysis.
Load-Settlement Behavior of Rock-socketed Drilled Shafts by Bi-directional Pile Load Test
Seol, Hoon-Il ; Jeong, Sang-Seom ; Han, Keun-Taek ; Kim, Jae-Young ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 61~70
Load settlement behaviors and load transfer characteristics of rock-socketed pile subjected bi-directional load at pile tip were investigated using bi-directional pile load tests (BD PLT) performed on ten large-diameter drilled shafts at four sites. Based on test results, additional pile-toe displacement (
) by coupled soil resistance was analyzed, and thus equivalent top loaded load-settlement curve of pile subjected bi-directional load was proposed by taking into account the coupled soil resistance. Through comparisons with field case studies, it is found that for test piles there exists effect of coupled soil resistance, which is represented by wbs, and thus an equivalent curve obtained by existing uncoupled methods can overestimate bearing capacity of piles by BD PLT. On the other hand, the analysis by the proposed method with soil coupling effect has a considerably larger settlement when compared with the results by uncoupled load transfer method and estimates reasonable load-settlement behaviors of test piles. In case of pile socketed in high strength rocks, however, effects of coupled soil resistance can be neglected.
Estimation of Ultimate Lateral Resistances of Piles Using CPT Cone Resistance in Sand
Kim, Min-Kee ; Kyung, Doo-Hyun ; Hong, Jung-Moo ; Lee, Jun-Hwan ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 71~77
In this study, CPT-based methodology for estimating the ultimate lateral resistance,
, is proposed and verified for lateral loaded piles in sandy soil. Preexistent methods estimating the ultimate lateral resistance,
, and the ultimate lateral capacity,
, of pile have been based on the vertical effective stress, relative density, and the coefficient of lateral earth pressure. Similarly, cone resistance
in pure sandy soil is expressed by those essential factors. As correlation between
are normalized with average effective stress
, estimation methodology for the lateral loaded pile of
in sandy soil is proposed. The method is verified by calibration chamber test results in pure sand. The standard derivation of estimated
is 0.279, and COV (Coefficient Of Variation) of estimated
is 0.272. These results showed that the estimated pus by the method are analogous with the measured
in calibration chamber test.
Characteristics of Undrained Cyclic Shear Behavior of Nak-Dong River Sand by Silt Contents
Kim, Young-Su ; Kim, Dae-Man ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 79~89
In this study, a series of undrained cyclic triaxial tests were performed with three different consolidation stress ratios (
=1.0, 1.5, 2.0) to investigate the undrained shear strength characteristics of sands with respect to the amount of contained silt located around the basin of Nak-dong River. The test results show that the more the sand has silt, the lower is cyclic shear stress ratio (CSR) in all
and that the higher
goes, the larger CSR decreases due to the increase of contained silt. The excessive pore pressure caused during shearing has an influence on the decrease of CSR by the high initial pore pressure in proportion to the amount of contained silt regardless of the
value. After consolidation, the analysis of the skeleton void ratio of the sample reveals that the main cause of the decrease of CSR as well as the increase of the initial excessive pore pressure is the increase of the skeleton void ratio in proportion to the amount of contained silt.
Evaluation of Strength Parameters of Cemented Sand
Lee, Hoon-Joo ; Choi, Sung-Kun ; Lee, Woo-Jin ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 91~100
This study proposes the equations evaluating the shear strength of cemented sand by analytical interpretation based on Mohr-Coulomb failure criteria, and verifies them using the results of triaxial and unconfined compression tests. The internal friction angle of cemented sand is identical to that of uncemented one regardless of the stress level, while the cohesion intercept of cemented sand is constant before the breakage of cementation bonds. Therefore, the shear strength of cemented sand can be represented as a summation of the shear strength of uncemented sand and the unconfined compressive strength of cemented sand. In addition, the cohesion intercept of cemented specimen can be expressed as a function of unconfined compressive strength and friction angle. In the transition zone, assuming a constant shear strength, the equations to evaluate shear strength and cohesion intercept of cemented sand are also represented. It is observed that the predicted values using these solutions agree well with the experimental results. The experimental results also show a linear relationship between the unconfined compressive strength and the breaking point of cementation bonds.
Influence of Water on Compression Characteristic of Decomposed Granite Soil Based on Single Particle Crushing Strength
Ham, Tae-Gew ; Kim, Uk-Gie ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 101~109
In order to investigate the influence of the water on compression characteristic of decomposed granite soils, a single particle crushing test and one-dimensional compression tests were carried out on three decomposed granite soils and Silica sand. The initial fracture strength for single particle reduced and variability of the strength increases due to weakening by existing water. Moreover, it was recognized that one-dimensional compression characteristic was related to the initial fracture strength characteristic, and the initial fracture strength also has the effect of weathering.
Strength Anisotropy through Artificial Weak Plane of Mudstone
Lee, Young-Huy ; Jeong, Ghang-Bok ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 111~120
The characteristic of induced anisotropy is investigated in this study for the Pohang mudstone involving the cut plane discontinuity. The uniaxial and triaxial compression tests are performed for anisotropic rocks with artificial joint to look into anisotropic strength characteristics. Both the uniaxial compressive strength and triaxial compressive strength show the lowest value at the angle of cut plane,
and the shoulder type of anisotropy is obtained. Anisotropy ratio (Rc) in uniaxial compression measures 9.0, whereas Rc=1.29-1.98 in triaxial compression is appeared. A series of analyses are made with the test results to derive the suitable parameter values when it is applied to the Ramamurthy (1985) failure criterion. The result of uniaxial compression test is analyzed by introducing the n-index into Ramamurthy failure criterion. The result shows that, n=l is suitable for
and n=3 is suitable for
. To analyze the result of triaxial compression test by Ramamurthy failure criterion, anisotropy ratio in uniaxial compression test is added to Ramamurthy's equation and material constants are estimated by modified Ramamurthy's equation. When these values are applied back to Ramamurthy failure criterion, the predicted values are well fitted to the test results. And strength anisotropy for failure criteria of Jaeger (1960), McLamore & Gray (1967) and Hoek & Brown (1980) are also investigated.
Evaluation of Hydraulic Conductivity of Slurry-wall-type Vertical Cutoff Wall with Consideration of Filter Cake
Nguyen, The Bao ; Lee, Chul-Ho ; Choi, Hang-Seok ; Kim, Sang-Gyun ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 121~131
In constructing a slurry trench cutoff wall, bentonite-water slurry is used to secure the stability of sidewalls during excavation before the wall is completed by backfilling. Unexpectedly, a thin but relatively impermeable layer called filter cake can be formed on the excavation surface, which significantly influences the result of slug test analysis in the cutoff wall if not considered. This study is to examine the effect of filter cake on evaluating hydraulic conductivity of the vertical cutoff wall through slug test analysis with the aid of the verified numerical program Slug_3D. The no-flux boundary conditions were adopted in Slug_3D to simulate the filter cake on the interface between the wall and the natural soil. A new set of type curves were built for applying the type curve method. New modification factors were obtained for using the modified line-fitting method. With consideration of filter cake, the type curve method and the modified line-fitting method were adopted to reanalyze the case study taken from EMCON (1995). The previous results achieved by Choi and Daniel (2006) without consideration of filter cake were compared with the present results obtained in this paper. The comparison emphasizes the necessity of considering filter cake when analyzing slug test results in vertical cutoff walls.
Estimation of Undrained Shear Strength for Clays Using Effective Cone Factor
Kim, Chang-Dong ; Kim, Soo-Il ; Lee, Jun-Hwan ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 133~141
In this study, a new method for estimating the undrained shear strength
of saturated clays using piezocone penetration test (CPTu) result is proposed. This is to develop more effective CPTu-based
estimation method at lower cost with less uncertainty. For this purpose, a marine clay deposit is selected and tested through extensive experimental testing program including both in-situ and fundamental laboratory tests. The proposed method is based on a correlation between the undrained shear strength
and the cone resistance
, without introduction of the total overburden stress into the
correlation. As a result, no additional testing procedure for collecting undisturbed soils samples is required, which can reduce overall testing cost. To verify the proposed method, 4 test sites, which consist of a variety of soil conditions, are selected and used for comparison between measured and predicted undrained shear strength. From comparison, it is seen that predicted values of
using the proposed method match well those from measured results.
Experimental Study on Pullout Behavior of Composite Type Ground Anchor
Hong, Seok-Woo ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 143~155
Ground anchors are classified depending on the kind of stress the grout is subjected to. If the grout material is subjected to tension then it is classified as tension anchor while when the grout material is subjected to compression it is classified as compression anchor. In this study a composite type anchor that possesses both the tension and compression mechanism was developed. For field tests, strain gauges were installed inside the anchor body in soft: soil. From the strain monitoring results, pull-out resistance mechanism that possesses both tension and compression strain was seen.
Analysis of Compressive Strength of Lightweight Air-mixed Soil According to the Properties of Soil
Song, Jun-Ho ; Im, Jong-Chul ; Hong, Seok-Woo ;
Journal of the Korean Geotechnical Society, volume 24, issue 11, 2008, Pages 157~166
To investigate the relationship between compressive strength (
) of Lightweight Air-mixed soil (LAS) and its physical deformation coefficient (
), a series of unconfined compressive tests have been performed on specimens of LAS according to various dredged soil types by percentage of sand, silt and clay. From the results it was found that the cement content (
) and unit weight (
) are most influence factors on strength, and percentage of sand, silt, clay by grain size analysis (KS F2302) have more effect on compressive strength than other physical properties of soil. It was also found that the rate of strength (a) increases with curing time, but it reduces with the increase of percentage of clay (