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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Geotechnical Society
Journal Basic Information
Journal DOI :
Korean Geotechical Society
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Volume & Issues
Volume 26, Issue 12 - Dec 2010
Volume 26, Issue 11 - Nov 2010
Volume 26, Issue 10 - Oct 2010
Volume 26, Issue 9 - Sep 2010
Volume 26, Issue 8 - Aug 2010
Volume 26, Issue 7 - Jul 2010
Volume 26, Issue 6 - Jun 2010
Volume 26, Issue 5 - May 2010
Volume 26, Issue 4 - Apr 2010
Volume 26, Issue 3 - Mar 2010
Volume 26, Issue 2 - Feb 2010
Volume 26, Issue 1 - Jan 2010
Selecting the target year
Effect of Stress History on CPT-DMT Correlations in Granular Soil
Lee, Moon-Joo ; Choi, Sung-Kun ; Kim, Min-Tae ; Lee, Ju-Hyeong ; Lee, Woo-Jin ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 7~16
Stress history increases the residual horizontal stress of granular soil and, consequently, the penetration resistance. This study analyzes the effect of stress history on the cone resistance (
), horizontal stress index (
) and dilatometer modulus (
) of CPT and DMT from calibration chamber specimen in OC as well as NC state. Test results show that the normalized cone resistance by mean effective stress correlates well with the relative density and the state parameter, whereas the normalized cone resistance by vertical effective stress is a little affected by stress history. The influence of stress history is more reflected on
, in which the effect of stress history on
is compensated by the at-rest coefficient of earth pressure,
, is related to relative density, state parameter and the normalized cone resistance by mean effective stress. It is also observed that the normalized dilatometer modulus by mean effective stress (
) shows a unique correlation with the state parameter, regardless of stress history.
Determination of Resistance Factors of Load and Resistance Factor Design for Drilled Shaft Based on Load Test
Kim, Seok-Jung ; Kwon, Oh-Sung ; Jung, Sung-Jun ; Han, Jin-Tae ; Kim, Myoung-Mo ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 17~24
Load Resistance Factor Design method is used increasingly in geotechnical design world widely and resistance factors for drilled shafts are suggested by AASHTO. However, these resistance factors are determined for intact rock conditions; by comparison, most of bedrocks in Korea have weathered condition, so that applying the AASHTO resistance factors is not reasonable. Thus, this study suggests the proper resistance factors for design of drilled shaft in Korea. The 22 cases of pile load test data from 8 sites were chosen and reliability-based approach is used to analyze the data. Reliability analysis was performed by First Order Second Moment Method (FOSM) applying 4 bearing capacity equations. As a result, when the Factor of Safety (FOS) was selected as 3.0, the target reliability indexes (
) were evaluated as 2.01~2.30. Resistance factors and load factors are determined from optimization based on above results. The resistance factors ranged between 0.48 and 0.56 and load factors for dead load and live load are evaluated as approximately 1.25 and 1.75 respectively. However, when the target reliabilities are considered as 3.0, the resistance factors are evaluated as approximately 50% of the results when the target reliability index was 2.0.
Rock Classification and Aggregate Evaluation of Tertiary Unconsolidated Deposits
Kim, Sung-Wook ; Lee, Kyu-Hwan ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 25~36
Tertiary unconsolidated mudstones spread throughout the eastern coast area. The demand for high quality filling materials in these areas is increasing due to harbors and large-scale residential land development. Rock produced in-situ or near site has been used as road subbase construction or reclamation materials for economical reason, but it is hard to decide appropriateness of quality specification because of its characteristics. The test results showed that unconsolidated rocks are diversely considered according to a different method of the applied geotechnical investigation. Therefore, the site of tertiary unconsolidated mudstones, the classification of rock and evaluation of rock properties that must be evaluated by objective criteria and apply a different set of criteria are needed. In addition, the environmental impact must be considered due to acid mine drainage.
Effect of Vibratory Injection on Grout Permeation Characteristics
Lee, Mun-Seon ; Kim, Jong-Sun ; Lee, Sung-Dong ; Choi, Young-Joon ; Yang, Jae-Man ; Lee, In-Mo ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 37~47
To improve the grout penetration characteristics, a vibratory grout injection technique was adopted in this study. It is a technique of grout injection in which an oscillating pressure is added to the steady-state pressure as an injection pressure. By applying the vibration during grout injection, cement particles will become less adhesive and the clogging tendency will be decreased. A series of pilot-scale chamber tests were performed to verify the enhancement of the groutability by applying the vibratory grout injection; assessment on the change of the lumped parameter
which represents a barometer of clogging phenomenon was made. Moreover, the effect of vibratory grout injection through the joint was also investigated using artificially made rock joints. Experimental results as well as analytical results show that the grout penetration depth can be substantially improved by vibratory grouting. Moreover, it was found that enhancement of the permeation grouting due to vibratory injection is more dominant at grouting pressure less than 400 kPa.
Evaluation of Particle Size Effect on Dynamic Behavior of Soil-pile System
Han, Jin-Tae ; Yoo, Min-Taek ; Yang, Eui-Kyu ; Kim, Myoung-Mo ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 49~58
This paper presents experimental results of a series of 1-g shaking table model tests performed on end-bearing single piles and pile groups to investigate the effect of particle size on the dynamic behavior of soil-pile systems. Two soil-pile models were tested twice: first using Jumoonjin sand, and second using Australian Fine sand. In the case of single-pile models, the lateral displacement was almost within 1% of pile diameter which corresponds to the elastic range of the pile. The back-calculated p-y curves show that the subgrade reaction of the Jumoonjin-sand-model ground was larger than that of the Australian Fine-sand-model ground at the same displacement. This phenomenon means that the stress-strain behavior of Jumoonjin sand was initially stiffer than that of Australian Fine sand. This difference was also confirmed by resonant column tests and compression triaxial tests. And the single pile p-y backbone curves of the Australian fine sand were constructed and compared with those of the Jumoonjin sand. As a result, the stiffness of the p-y backbone curves of Jumunjin sand was larger than those of Australian fine sand. Therefore, using the same p-y curves regardless of particle size can lead to inaccurate results when evaluating dynamic behavior of soil-pile system. In the case of the group-pile models, the lateral displacement was much larger than the elastic range of pile movement at the same test conditions in the single-pile models. The back-calculated p-y curves in the case of group pile models were very similar in both sands because the stiffness difference between the Jumoonjin-sand-model ground and the Australian Fine-sand-model ground was not significantly large at a large strain level, where both sands showed non-linear behavior. According to a series of single pile and group pile test results, the evaluation group pile effect using the p-multiplier can lead to inaccurate results on dynamic behavior of soil-pile system.
A Comparison on the Effect of Soil Improvement Methods for the Remediation of Heavy Metal Contaminated Farm Land Soil
Yun, Sung-Wook ; Jin, Hae-Geun ; Kang, Sin-Il ; Choi, Seung-Jin ; Lim, Young-Cheol ; Yu, Chan ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 59~70
A long-term field demonstration experiment on selected stabilization methods to reduce the heavy metal mobility in farmland soil contaminated by heavy metals was conducted. The field demonstration experiment was established on the contaminated farmland with wooden plates (thickness = 1 cm), of which the dimension were width = 200 cm, Length = 200 cm, height = 80 cm, filled with treated soil, which was mixed with lime stone and steel refining slag except on control plot. Soil samples in the plots were collected and analyzed during the experiment period (6 months) after the installation of the plots. The field demonstration experiment results showed that the application lime stone at the ratio of 5% was effective for immobilizing heavy metal components in contaminated farmland soil.
The Freezing Characteristics of Pavement Layer Using the Field Road Model Test
Shin, Eun-Chul ; Ryu, Byung-Hyun ; Park, Jeong-Jun ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 71~80
Korea is considered to be a seasonal frozen soil area that thaws in the spring, and freezes in winter. In the current design codes for anti-freezing layer, the thickness of anti-freezing layer is calculated by the depth frozen due to the temperature condition. Therefore, there is a tendency of over-design and applying uniform thickness without the consideration of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential to study the structural appropriateness of pavement layer and bearing capacity besides the seasonal and mechanical properties of pavement materials to take an appropriate and reasonable design of the road structure. In this paper, the evaluation of frost susceptibility on subgrade, ant-freezing layer, subbase was conducted by means of the mechanical characteristics and model experiment. The temperature, heaving amount, unfrozen water contents and freezing depth of soil samples, the subgrade, anti-freezing layer, subbase soils of road construction site were measured to determine the frost susceptibility.
Evaluation on the Effect of Coal-ash as Landfill Cover Material of Mono-Layer Cover System through the Field Scale Test
Yun, Sung-Wook ; Kang, Sin-Il ; Jin, Hae-Geun ; Kim, Pil-Joo ; Kim, Soon-Oh ; Yu, Chan ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 81~91
In order to investigate the applicability and suitability of the coal ash (bottom ash) to landfill final cover, field pilot-scale lysimeter experiments were carried out. The mixture of loamy soil, bottom ash, and construction waste was placed as a cover material in lysimeter (
) which were constructed with cement brick, and then volumetric water contents, pF value, and the quantity of runoff and seepage of treatment boxes filled with the mixture of loamy soil and the industrial by-products were monitored from July, 2007 to february, 2008. Among the cases tested, consequently, the case containing the mixture of bottom ash and loamy soil was most effective in plant growth and water retention ability.
Evaluation of Performance of Grouts and Pipe Sections for Closed-loop Vertical Ground Heat Exchanger by In-situ Thermal Response Test
Lee, Chul-Ho ; Park, Moon-Seo ; Min, Sun-Hong ; Choi, Hang-Seok ; Sohn, Byong-Hu ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 93~106
In performing a series of in-situ thermal response tests, the effective thermal conductivities of six vertical closed-loop ground heat exchangers were experimentally evaluated and compared one another, which were constructed in a test bed in Wonju. To compare thermal efficiency of the ground heat exchangers in field, the six boreholes were constructed with different construction conditions: grouting materials (cement vs. bentonite), different additives (silica sand vs. graphite) and the shape of pipe-sections (general U-loop type vs. 3 pipe-type). From the test results, it can be concluded that cement grouting has a higher effective thermal conductivity than bentonite grouting, and the efficiency of graphite better performs than silica sand as a thermally-enhancing addictive. In addition, a new 3 pipe-type heat exchanger provides less thermal interference between the inlet and outlet pipe than the conventional U-loop type heat exchanger, which results in superior thermal performance. Based on the results from the in-situ thermal response tests, a series of economic analyses have been made to show the applicability of the new addictives and 3 pipe-type heat exchanger.
Study on Cement-based Grout for Closed-loop Vertical Grout Heat Exchanger
Park, Moon-Seo ; Wi, Ji-Hae ; Lee, Chul-Ho ; Choi, Hang-Seok ; Kang, Shin-Hyung ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 107~115
In this paper, the applicability of cement grout bas been studied as an alternative to bentontite grout to backfill ground heat exchangers. To provide an optimal mixture design, the groutabilty and thermal conductivity of cement grouts with various mixture ratios were experimentally evaluated and compared. The unconfined compression strength of cement grout specimen was measured, which was exposed to cyclic temperature variation ranging from
. In addition, the integrity of the interface between circulating HDPE pipes and cement grout was evaluated by performing equivalent hydraulic conductivity tests, on the specimen. in which a pipe locates at the center of the specimen.
Behavioral Mechanism of Hybrid Model of Soil-nailing and Compression Anchor
Seo, Hyung-Joon ; Kim, Hyun-Rae ; Jeong, Nam-Soo ; Lee, In-Mo ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 117~133
A hybrid system of soil-nailing and compression anchor is proposed in this paper; the system is composed of an anchor bar (installed at the tip) with two PC strands and a steel bar. After drilling a hole, installing proposed hybrid systems, and filling the hole with grouting material, prestress is applied to the anchor bar to restrict the deformation at the head and/or to prevent shallow slope failures. However, since the elongation rate of PC strand is much larger than that of steel bar, yield at the steel bar will occur much earlier than at the PC strand. It means that the yield load of the hybrid system will be overestimated if we simply add yield loads of the two - anchor bar and PC strands. It might be needed to try to match the yielding time of the two materials by applying the prestress to the anchor bar. It means that the main purpose of applying prestress to the anchor bar should be two-fold: to restrict the deformation at the nail head; and more importantly, to maximize the design load of the hybrid system by utilizing load transfer mechanism that transfers the prestress applied at the tip to the head through anchor bar. In order to study the load transfer mechanism in a systematic way, in-situ pullout tests were performed with the following conditions: soil-nailing only; hybrid system with the variation of prestress stresses from 0 kN to 196 kN. It was found that the prestress applied to the anchor system will induce the compressive stress to the steel bar; it will result in decrease in the slope of load-displacement curve of the steel bar. Then, the elongation at which the steel bar will reach yield stress might become similar to that of PC strands. By taking advantage of prestress to match elongations at yield, the pullout design load of the hybrid system can be increased up to twice that of the soil-nailing system.
The Bearing Capacity Characteristics of Top Base Foundations in Cohesionless Soils
Kim, Chan-Kuk ; Kim, Hak-Moon ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 135~145
Top Base Foundation (TBF) is widely used for the increment of bearing capacity and restraining settlement of foundations when the bearing capacity of ground is not enough. The design of bearing capacity obtained from exiting Japanese standard underestimates considerably what is compared with the observation values from the field measurement. Therefore, intensive model tests and site observation programs are carried out to establish more reasonable prediction technique and understanding of TBF in soft ground. In this study, 1/5 scale model tests are performed in order to investigate the behavior of TBF with various shapes in a laboratory. Also, about 100 sites measurement data are evaluated to investigate the field behavior of TBF in various ground conditions. Based on the results of the model tests and field measurement data, it was possible to introduce more reasonable bearing capacity equations of TBF considering N-value of soils, the effect of underground water and failure mechanisms.
The Optimization of Hyperbolic Settlement Prediction Method with the Field Data for Preloading on the Soft Ground
Choo, Yoon-Sik ; Kim, June-Hyoun ; Hwang, Se-Hwan ; Chung, Choong-Ki ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 147~159
The settlement prediction is very important in preloading method for a construction site on the soft ground. At the design stage, however, it is hard to predict the settlement exactly due to limitations of the site survey. Most of the settlement prediction is performed by a regression settlement curve based on the field data during construction. In Korea, hyperbolic method has been most commonly used to align the settlement curve with the field data, because of its simplicity and many application cases. The results from hyperbolic method, however, may differ by data selections or data fitting methods. In this study, the analyses using hyperbolic method were performed about the field data of
site in Pusan. Two data fitting methods, using an axis transformation or an alternative method which is a direct regression method, were applied with various data groups. If data was used only after the ground water level being stabilized, fitting results using both methods were in good agreement with the measured data. Regardless of the information about the ground water level, the alternative method gives better results with the field data than the method using an axis transformation.
Reliability Updates of Driven Piles Based on Bayesian Theory Using Proof Pile Load Test Results
Park, Jae-Hyun ; Kim, Dong-Wook ; Kwak, Ki-Seok ; Chung, Moon-Kyung ; Kim, Jun-Young ; Chung, Choong-Ki ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 161~170
For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was obrained based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability indices of driven steel pipe piles by adding more proof pile load test results, even not conducted to failure, to the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. The empirical method proposed by Meyerhof is used to calculate the predicted pile resistance. Reliability analyses were performed using the updated distribution of pile resistance ratio. The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian updates are most effective when limited data are available for reliability analysis.
Case Study of the Characteristic of Ground Deformation and the Strut Axial Force Change in Long Span Deep Excavation
Kim, Sung-Wook ; Han, Byung-Won ;
Journal of the Korean Geotechnical Society, volume 26, issue 7, 2010, Pages 171~186
It is generally known that the mechanism of behavior in the flexible earth retaining system is relatively more complicated than in the rigid earth retaining system. Moreover in the case of long span strut supporting system the analysis of strut axial force change becomes more difficult when the differences of ground condition and excavation work progress on both sides of excavation section are added. When deeper excavation than the specification or installation delay of supporting system or change of ground condition happen during construction process, lots of axial force can be induced in some struts, which threaten the safety of construction. This paper introduces two examples of long span deep excavation where struts and rock bolts were used as a supporting system with flexible wall structure. The characteristics of ground deformation and strut axial force change, which were measured in the sections of two examples that are 50 meters apart in one construction site and have almost similar design and construction conditions were analysed, the similarity and difference between measurement results of two examples were compared and investigated. This article aims to improve and develop the technique of design and construction in future projects having similar ground condition and supporting method.