• Geotechnical Engineering
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• v.11 no.2
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• pp.19-28
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• 1995

Based on the various test data acquired in the field, the large pressure chamber and the small pressure chamber, uplift behaviors and method of determining the ultimate uplift capacity of pile driven in small pressure chamber were studied. After uplift pile experienced 2 or 3 sudden slip due to increase of uplift load, complete pullout failure was occurred. Thus, it appears that the ultimate uplift capacity could be identified as the load at displacement where first slip occurs. The ultimate uplift capacity might be determined in every test and the disturbance after first uplift test could be recovered by adding one blow of the drop hammer, which had to depend on the model pile capacity.

• Journal of the Korean GEO-environmental Society
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• v.24 no.1
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• pp.5-14
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• 2023

In this study, the load transfer characteristics of the base and skin of drilled shafts were analyzed and the load sharing ratio was calculated by performing a load transfer large-scale model test and three-dimensional numerical analysis considering the similarity of drilled shafts, which is the design target. From the linear behavior of drilled shafts shown in the large-scale model test and 3D numerical analysis results, the skin load transition curve for the design conditions of this study was proposed by Baquelin et al., and the base load transition curve was proposed by Baquelin et al. For the horizontal load transition curve, the formula proposed by Reese et al. was confirmed to be appropriate. The test value was slightly larger than the numerical analysis value for the axial load at the rock socketing, but the load sharing ratio at the rock socketing increased, on average, about 27.8% as the vertical load increased. The analysis value of the vertical settlement of the pile head under the vertical load was evaluated to be slightly smaller than the test value, and the maximum vertical settlement of the pile head in the model test and analysis maximum vertical load was 10.6 mm in the test value and 10.0 mm in the analysis value, and the maximum vertical settlement value at the base of the pile was found to be a test value of 2.0 mm and an analysis value of 1.9 mm. The horizontal displacement at the head of the column (ground surface) and the head of the pile during the horizontal load was found to agree relatively well with the test value and the analysis value. As a result of the model soil test, the horizontal load measured at the maximum horizontal displacement of 38.0 mm was evaluated to be 24,713 kN, and the horizontal load in the numerical analysis was evaluated to be 26,073 kN.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.5-16
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• 2005

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.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.131-139
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• 2004

When calculating bearing capacity and settlement of actual foundation from plate test result fur design and construction of shallow foundation, scale effect should be considered. But, adequate guide and test result of scale effect were not prepared yet in Korea. So, to analyze the relations of bearing capacity and settlement as the difference of loading plate sizes, model test and field loading test were performed with different loading plate on weathered-granite layer. Model tests were conducted with water content, compaction number, saturated unit weight and plate size(Dl5, 25cm) in soil-box$(2,000\times 2,000\times 1,000mm)$ formed soil layer. Field loading tests were carried out with diameters of loading plate$(D15, 25, 30, 40, 75\times 75, 140\times 210cm)$ on the same soil condition. Finally, we presented the prediction formula of bearing and settlement for computating scale offset in design of shallow foundation through result analysis of load test and numerical simulation on weathered soil and rock.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.535-545
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• 2022

Improving the stability of the ground in seismic design requires an understanding of the dynamic behavior of the ground under seismic loads. The shaking table test is an important methodology to provide this understanding. This study aimed to assess the influence on boundary conditions, as they are among the most important factors affecting the test. This was achieved by testing the influence of boundary conditions on the seismic responses of model slopes at different locations in the testing apparatus. A model slope was fabricated at different locations in a laminar shear box, and the influence of the boundary conditions was then measured. Each model slope was created at 100, 50, and 25 cm from the soil wall, and sine wave seismic loads of the same size were inputted. The results confirmed that the acceleration was amplified by the influence of the boundary in the case of the slope being located 25 cm from the boundary, whereas the influence of the boundary conditions decreased when the slope was located at 50~100 cm.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.63-74
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• 2019

Numerical liquefaction model and response history analysis procedure are verified based on dynamic centrifuge test results. The test was a part of the Liquefaction Experiments Analysis Project (LEAP). The model ground was formed inside of rigid box by using the submerged Ottawa F65 sand with a relative density of 55% and 5° of surface inclination. A tapered sinusoidal wave with a frequency of 1 Hz was applied to the base of the model box. Numerical analyses were performed by two dimensional finite difference method in prototype scale. The soil is modeled to show hysteretic behavior before shear failure, and Mohr-Coulomb model is applied for shear failure criterion. Byrne's liquefaction model was applied to track the changes in pore pressure due to cyclic loading after static equilibrium. In order to find an appropriate flow condition for the liquefaction analysis, numerical analyses were performed both in drained and undrained condition. The numerical analyses performed under the undrained condition showed good agreement with the centrifuge test results.

• Proceedings of the Korean Geotechical Society Conference
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• 1996.10a
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• pp.277-284
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• 1996

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.77-83
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• 2012

Recently, excavations using propped walls were popularized in downtown due to reduced settlement of nearby structures. These excavations is induced strain to propped walls or settlement in near ground. In this study, the ground reinforcing effect was proven using NDS, which is an inorganic injection material. Injection tests were performed to compute optimum injection pressure and volume. Next, calibration chamber tests were performed by using computed injection pressure and volume, and wall behaviour was examined for overburden pressures of 50kPa and 150kPa. Ground reinforcing effect was shown when the material behind the propped wall was grouted. From test results, optimum injection pressure was 350kPa and the optimum volume was 10L considering economics. Calibration chamber test results show that after the material was grouted, the maximum settlement was reduced to 19% of the non-grouted condition. For overburden pressures of 50kPa and 150kPa behind the wall, the settlement of the wall increased by 58% and 57% when compared to the case of no overburden pressure.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.41-48
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• 2004

Several centrifuge modelling tests were performed to compare sand compaction pile (SCP) with gravel compaction pile (GCP) at the point of bearing capacity. SCP and GCP were installed as 30, 40, 50, 60, 70% of replacement ratio in cylindrical model tank (diameter = 20 cm, height = 40 cm), and the loading tests were carried out to analyze the bearing characteristics of soft clay ground reinforced by SCP and GCP. As a result of loading tests, the bearing capacities of soft grounds reinforced by SCP and GCP increase with increasing replacement ratio of pile, and a GCP reinforced ground has larger bearing capacity than that of a SCP reinforced ground. Several proposed bearing capacity equations for ground reinforced by SCP or GCP were compared with loading test results.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.117-128
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• 2000

Sand compaction pile(SCP) is one of the ground improvement techniques which is being used for not only accelerating consolidation but also increasing bearing capacity of loose sands or soft clay grounds. In this study, laboratory model test and large-scale direct shear test were performed to investigate the effects of area replacement ratio of composite ground in order to find out the optimum value of area replacement ratio for the ground improvement purpose. Area replacement ratios of 20%, 30%, 40%, 50%, 60% were chosen respectively in the model tests to study the effects of area replacement ratio on variations of stress concentration ratio, settlement and shear strength characteristics of composite ground. In large-scale direct she4ar tests, area replacement ratios of 20%, 30%, 46% were applied to study their effects on shear strength characteristics of composite ground.