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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 21, Issue 10 - Dec 2005
Volume 21, Issue 9 - Nov 2005
Volume 21, Issue 8 - Oct 2005
Volume 21, Issue 7 - Sep 2005
Volume 21, Issue 6 - Aug 2005
Volume 21, Issue 5 - Jul 2005
Volume 21, Issue 4 - Jun 2005
Volume 21, Issue 3 - Apr 2005
Volume 21, Issue 2 - Mar 2005
Volume 21, Issue 1 - Feb 2005
Selecting the target year
Micro In-situ Tests on Overconsolidated Clay Prepared in Chambers
Cho Nam Jun ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 5~16
Tn this study, model soil deposits are prepared in large test chambers to minimize the scale effects. Also, slurry of mixture containing 50 percent kaolin clay and 50 percent silica has been consolidated to simulate the process of natural soil deposit formation and to reduce the consolidation time. To provide a more detailed description of varying soil properties along the soil profile of model clay deposits and to compare the in-situ test results with those from prototype tests, miniature in-situ tests, including vane shear, piezoprobe, and cone penetration tests were conducted in each of the clay deposits. The current results indicate that consistent soil deposits were prepared for the current and previous test programs. Also, reasonable predicting methods of prototype behavior based on model in-situ test results were suggested in this study by examining differences between the test results from both the model and prototype tests.
Soil Water Characteristic Curve for Weathered Granite Soils - A Test Method
Lee Sung Jin ; Lee Seung Rae ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 17~26
Soil water characteristic curve (SWCC) is a unique characteristic that should be considered In the analysis of unsaturated soil and prediction of unsaturated properties. However, the volume change of soil specimens that happens in the existing apparatus affects the SWCC, Therefore, In this study, we intended to obtain more appropriate SWCC by measuring the change In the volume of the specimen in the SWCC tests. The measured change of void ratio indicates that the saturation step prior to the test changes the original structure of the soil specimen. Thus we carried out the test far the same specimen omitting the saturation step prior to the test. The change of void ratio by this test procedure is relatively small.
Performance of Innovative Prestressed Support Earth Retention System in Urban Excavation
Kim Nak Kyung ; Park Jong Sik ; Jang Ho Joon ; Han Man Yop ; Kim Moon Young ; Kim Sung Bo ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 27~36
The performance of innovative prestressed support (IPS) earth retention system applied in urban excavation was presented and investigated. The IPS wales provide a high flexural stiffness to resist the bending by lateral earth pressure, and the IPS wales transfer lateral earth pressure to Corner struts. The IPS wale provides a larger spacing of support, economical benefit, construction easiness, good performance, and safety control. In order to investigate applicability and stability of the IPS earth retention system, the IPS system was instrumented and was monitored during construction. The IPS system applied in urban excavation functioned successfully. The results of the field instrumentation were presented. The measured performances of the IPS earth retention system were investigated and discussed.
System Identification Analysis on Soil-Structure Interaction Using Field Data
Kim Seung Hyun ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 37~46
In the field of earthquake engineering, recent improvements in many areas, such as seismological source modeling, analysis of travel path effects, and characterization of local site effects on strong shaking, have led to significant advances in both code-based and more advanced procedures for evaluating earthquake ground motions. A missing link, however, is empirically verified design procedures fur assessing the effects of soil-structure interaction (SSI). Available Soil-Structure Interaction (SSI) analysis techniques range from simple substructure-type procedures to relatively sophisticated finite element procedures. The most common substructure approach for foundation-soil interaction is to use a frequency-dependent and complex-valued impedance function. This study uniquely evaluates impedance functions for two well-instrumented sites w significant inertial SSI effects using a system Identification technique. The system identification analysis results are then compared to predictions from a simple theoretical model to gain insight into the inertial interaction effect in the subject sites.
Group Effects in Pile Group under Lateral Loading
Ahn Kwang Kuk ; Kim Hong Taek ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 47~55
This paper describes the results for a numerical analysis of'single piles and pile oops in clayey soils subjected to monotonous lateral loading using the ABAQUS finite element software. The investigated variables in this study include free head and embedded capped single piles, pile diameter (1.0 m, 0.5 m), pile length (7.0 m, 10.0 m), and pile groups. The 1
3 pile group was selected to investigate the individual pile and group lateral resistance, the distribution of the resistance among the piles, the effects of lateral stresses in front of and on the sides of the piles, and the effect of a cap on the lateral resistance of the leading pile. The soil was modeled using Cam-clay constitutive relationship and the pile was considered as a elastic circular concrete pile. The results show that the size of the cap influences lateral capacity of sin pile. The results also show in pile groups, the pile-soil-pile interaction and the cap effect the resistance in the leading pile, and the p-multiplier for the leading pile of greater than 1.0 was able to be obtained.
Hydraulic Stability and Wave Transmit Property of Stacked Geotextile Tube by Hydraulic Model Test
Oh Young In ; Shin Eun Chul ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 57~65
Geotextile have been used for the past 30 years for various types of containers, such as small sandbag, 3-D fabric forms and aggregate filled gabion etc. While they are mainly used for flood and water control, they are also used against beach erosion fir shore protection. Especially, large-sized geotextile tube structures are used in various innovative coastal systems involving breakwaters. This paper presents the hydrodynamic behavior of geotextile tubes based on the results of hydraulic model tests. These tube are generally about 1.0 m to 2.0 m in diameter, thou띤 they can be sized for any application. The tubes can be used solely, or stacked to add greater height and usability. Stacked geotextile tubes will be created by adding the height necessary for some breakwaters and embankment, therefore increasing the usability of geotextile tubes. The hydraulic model test was conducted as structural condition and wave conditions. Structural condition is installation direction to the wave (perpendicular and 45
$), and wave condition is varied with the significant wave height ranging from 3.0 m to 6.0 m. Compared with previous test result, the stacked geotextile tube is more stable against wave attack than single tube. Also, the case of none-water depth above crest is more stable than 0.5H of water depth above crest. The incline installed stacked tube is more effective for wave adsorption.
Effects of Geosynthetic Reinforcement on Compaction of High Water Content Clay
Roh Han Sung ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 67~84
This research was conducted to evaluate the effectiveness of reinforcement for nearly saturated soft clay compaction. The effectiveness was investigated by roller compaction test using nearly saturated clay specimens. The nearly saturated condition was obtained by submerging clay in the water for 12 hours. High water content specimens were compacted in plane strain condition by a steel roller. A specimen was compacted by four 5 cm horizontal layers. Specimens were prepared fur both reinforced and unreinforced cases to evaluate the effectiveness of reinforcement. Used reinforcement is a composite consisted of both woven and non-woven geotextile. The composite usually provides drainage and tensile reinforcement to hi인 water-contented clay so that it increases bearing capacity. Therefore, large compaction load can be applied to reinforced clay and it achieves higher density effectively. The reinforcement also increases compaction efficiency because it reduces the ratio between shear and vertical forces during compaction process. The maximum vertical stress on the base of specimen usually decreased with higher compaction thickness. The reinforcement increases soil stiffness under the compaction roller and it initiates stress concentration. As a result, it maintains higher vertical stress level on the base of specimen that provides better compaction characteristics. Based on test results, it can be concluded that the reinforcement is essential to achieve effective compaction on soft clay.
P-S Characteristics for End-bearing Pile in Granular Material
Lee Yong Joo ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 85~91
This paper investigates P-S (load-settlement) relationship for the end-bearing Pile in granular material using the CRISP FE Program with the laboratory 2D model pile load test. In order to simulate the effect of end-bearing pile problem in the FEA, the author adopts several forms of slip element around the pile length and the pile tip. Through this study it was found that e degree of non-associated Plastic flow rule incoporated into the Mohr-Coulomb model for the end-bearing pile with the slip elements was a dominant factor in terms of numerical solution convergence. In contrast, the roller boundary used along the pile shaft showed a smooth convergence with respect to the degree of non-associated plastic flow rule.
Complex Permittivity of Sand at Low Frequency
Oh Myoung Hak ; Kim Yong Sung ; Park Jun Boum ; Yoon Hyun Suk ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 93~103
This study was performed to identify the presence of measurement distortions such as electrode polarization and to investigate the influence of soil water content on complex permittivity at low frequency. In low frequency measurement using two-terminal electrode system, electrode polarization effect was observed at frequencies less than approximately 100 HBz. The analysis for real permittivity should be performed at frequencies above 100 kHz in order to exclude electrode polarization effect in the analysis of real permittivity at low frequency measurements. For a given soil, both of real and effective imaginary permittivity of wet soil increased continuously with volumetric water content. This is evidenced by the facts that the real permittivity is proportional to the number of dipole moments per unit volume and effective imaginary permittivity is effected by the conduction due to water. However, proportional relation between real permittivity and volumetric water content is valid at upper MHz frequencies.
Dynamic Behaviors of Behavior Piles and Countermeasures to Improve Their Seismic Performance Using Shaking Table Tests
Hwang Jae Ik ; Lee Yong Jae ; Han Jin Tae ; Kim Myoung Mo ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 105~111
Shaking table tests are performed to investigate the seismic behavior of the batter pile and to bring up the countermeasures to improve the seismic performance of the batter pile. First of all, this study demonstrates how batter piles and vertical piles behave under static lateral loadings. Secondly, the vulnerability of batter plies under dynamic lateral loadings is demonstrated showing the axial forces and bending moments mobilized at the pile heads during shaking table tests. Thirdly, countermeasures to overcome the vulnerability of behavior piles during earthquakes are pursued. The countermeasures investigated in this study include introduction of a rubber element at the pile head and the deck plate connection, and introduction of hinge connection. Finally, the slope of batter piles which induces the minimum pile forces during the dynamic loadings are investigated and found to be 8:3 (Vertical to Horizontal).
A Review on Ultimate Lateral Capacity Prediction of Rigid Drilled Shafts Installed in Sand
Cho Nam Jun ; Kulhawy F.H ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 113~120
An understanding of soil-structure interaction is the key to rational and economical design for laterally loaded drilled shafts. It is very difficult to formulate the ultimate lateral capacity into a general equation because of the inherent soil nonlincarity, nonhomogeneity, and complexity enhanced by the three dimensional and asymmetric nature of the problem though extensive research works on the behavior of deep foundations subjected to lateral loads have been conducted for several decades. This study reviews the four most well known methods (i.e., Reese, Broms, Hansen, and Davidson) among many design methods according to the specific site conditions, the drilled shaft geometric characteristics (D/B ratios), and the loading conditions. And the hyperbolic lateral capacities (H
) interpreted by the hyperbolic transformation of the load-displacement curves obtained from model tests carried out as a part of this research have been compared with the ultimate lateral capacities (Hu) predicted by the four methods. The H
ratios from Reese's and Hansen's methods are 0.966 and 1.015, respectively, which shows both the two methods yield results very close to the test results. Whereas the H
predicted by Davidson's method is larger than H
, the C.0.V. of the predicted lateral capacities by Davidson is the smallest among the four. Broms' method, the simplest among the few methods, gives H
: 0.896, which estimates the ultimate lateral capacity smaller than the others because some other resisting sources against lateral loading are neglected in this method. But it results in one of the most reliable methods with the smallest S.D. in predicting the ultimate lateral capacity. Conclusively, none of the four can be superior to the others in a sense of the accuracy of predicting the ultimate lateral capacity. Also, regardless of how sophisticated or complicated the calculating procedures are, the reliability in the lateral capacity predictions seems to be a different issue.
Modelling of Soil Extraction Technique for Restoration of Building Tilt from Geotechnical Centrifuge Tests
Lee Cheol Ju ; Ng C.W.W. ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 121~126
It is not uncommon to observe tilt of buildings and towers as a result of unexpected differential foundation settlements. Over the years, a number of engineering methods including the soil extraction technique have been attempted to reduce inclination of buildings and towers. In this research, a series of novel geotechnical centrifuge model tests by using a state-of-the-art in-flit robotic manipulator have been conducted to study key factors which govern the restoration of building tilts. In the centrifuge model tests, the robotic manipulator was used to drill and extract soil in-flight near an initially tilted model building. The soil extraction was to induce stress release, thereby mitigating the inclination of the model building. Insights into the effects of different configurations, soil density and sequences of drilling observed during the centrifuge model tests on the restoration of the model building are to be investigated.
Coupled Effect of Soil Nail/Slope Systems
Jeong Sang Seom ; Lee Jin Hyung ; Lee Sun Keun ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 127~135
In this paper, a numerical comparison of predictions by limit equilibrium analysis and finite difference analysis is presented for slope/soil-nail system. Special attention is given to the coupled analysis based on the explicit-finite-difference code, FLAC 2D. To this end, an internal routine (FISH) was developed to calculate a factor of safety for a soil nail slope according to shear strength reduction method. The case of coupled analyses was performed for soil nails in slope in which the soil nails response and slope stability are considered simultaneously. In this study, by using these methods, the failure surfaces and factors of safety were compared and analyzed in several cases, such as toe, middle and top of the slope, respectively. Furthermore, the coupled method based on shear strength reduction method was verified by the comparison with other analysis results.
A Study on Improvement of Shear Test Apparatus in the Direct Shear Test Under Constant Pressure
Kim Jae Young ; Yang Tae Seon ; Akihiko Ohshima ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 137~144
A direct shear test is classified roughly by one side simple shear test of confining horizontal displacement type and torsional shear test of non-confining one. Direct shear test that has been widely used so far has some problems with test apparatus, testing and the analysis, and in particular that its strength value is everestimated in sandy soils. Also, progressive failure of shearing process happens from shear apparatus restriction and because the shear strain and shear stress are erratic in specimen, we can not define the shear strain value. In the meantime, a simple shear test having advantage of direct shear test is an ideal test method that can get stress-strain relation on shear because it can deliver constant shearing deformation to specimen. However, simple shear test cannot be used practically, because its structure makes tester manufacturing difficult. This paper described a on outline of test apparatus, improvement of test method, and constant pressure test results based on the obtained from improved direct shear apparatus and the standardization of JGS soil testing method.
Predicting the Failure of Slope by Mathematical Model
Han Heui Soo ; Chang Ki Tae ;
Journal of the Korean Geotechnical Society, volume 21, issue 2, 2005, Pages 145~150
It is useful to select an appropriate mathematical model to predict landslide. Through observation and analysis of real-time measured time series, a reasonable mathematic model is chosen to do prediction of landslide. Two theoretical models, such as polynomial function and growth model, are suggested for the description and analysis of measured defermation from an active landslides. These models are applied herein to describe the main characteristics of defermation process for two types of landslide, namely polynomial and growth models. The TRS (tensiof rotation and settlement) sensors are applied to adopt two models, and the data analysis of two field (Neurpjae and Buksil) resulted in good coincidence between measured data and models.