• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.947-954
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• 2008

Waste landfills built on weak soils have the possibilities of the failure of slope and foundation due to the disposed waste loads. To ensure the landfill will sustain its stability within a limited site area, it's necessary to investigate and understand the characteristics of soft land by identifying the requirements for waste filling and by quantitative field measurement and management of landfills. In this paper, the stability analyses are performed using the field measurement data of Gimpo #2 Metropolitan Landfil. For the stability analysis, Tominaga-Hashimoto method and Kuriharh method, which may be able to manage the stability of the landfill quantitatively, are used.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.119-126
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• 2008

Ground stiffness(shear wave velocity) is one of the key parameters in geotechnical earthquake engineering. An In-situ seismic technique has its own advantages and disadvantages over the others in stiffness measurements. By combining the crosshole and seismic cone techniques and utilizing favourable features of bender elements, a new hybrid probe has been developed in order to enhance data quality and easiness of testing. The basic structure of the probe, called "MudFork", is a fork composed of two blades, on each of which source and receiver bender elements were mounted respectively. To evaluate the disturbance caused by the penetration of the probe, shear wave velocity measurements were carried out in the Kaolinite slurry in the laboratory. Finally, the probe was penetrated in coastal mud near Incheon, Korea, using SPT(standard penetration test)rods pushed with a routine boring machine and shear wave velocity measurements were carried out. The results were verified with data from laboratory and cone testing. The performance of the probe turns out to be excellent in terms of data quality and testing convenience.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.163-170
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• 2010

Today, In-Situ testing for measureing geotechnical characterization are divided by Cone Penetration Test, Standard Penetration Test and Dilatometer Test, and will vary depending on soil conditions have been applied (Korea Geotechnical Engineering, 2006). However, these methods can be applied on sand or soft clay soil. Now, many studies are progressing for evaluating the stiffness characteristic of rocks and IGM. and Nam moon suk(2006) did Texas Cone Penetrometer Test for designing field penetration pile intruded at rocks and IGM. but, reliability of Texas Cone Penetration Test has confidence limits because TCPT is testing in Texas centrally, and energy dose not measure Woojin Lee, etc. (1998) did calculate Standard Penetration Test Hammer's dynamic energy efficiency by using dongjaeha analyzer. this research, we installed strain gage and accelerometer for supply existing equipment, and develop MCP that can use variety soils. this thesis, we measured energy at head and tip of Rod for evaluating energy that transport at free falling. As a result, Energy differences are occurred at head and tip of Rod.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.198-207
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• 2010

Many methods and techniques have been developed to obtain the accurate design parameters in soft soils. In particular, several researchers suggest the techniques to get the void ratio for understanding the soil behavior. The objective of this paper verifies the accuracy of the proposed analytical solution for determining the void ratio based on the elastic wave velocities. The paper covers the theories of Wood, Biot, Gassmann and Foti proposed chronological order. The total theory represents the wave propagation in fully saturated medium. To verify the proposed analytical solution, the laboratory and field tests are carried out. After measuring the elastic wave, the void ratios are assessed using proposed equation. The volume based void ratios are also obtained for comparing with the estimated value by several equations. The values estimated by volume, Gassmann and Biot are show good similarity. However, the void ratios based on Wood and Foti methods have a slightly different trend. This study suggests that the theories of Biot and Gassmann may be a useful equation for assessing the void ratio using elastic wave velocities in the field.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.987-997
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• 2008

Successful design, construction and maintenance of geotechnical structure in soft ground and marine clay demands prediction, control, stability estimation and monitoring of settlement with high accuracy. It is important to predict and to estimate the compression index of soil for predicting of ground settlement. Lab. and field tests have been and are indispensable tools to achieve this goal. In this paper, Artificial Neural Networks (ANNs) model with Levenberg-Marquardt Algorithm and field database were used to predict compression index of soil in Korea. Based on soil property database obtained from more than 1800 consolidation tests from soils samples, the ANNs model were proposed in this study to estimate the compression index, using multiple soil properties. The compression index from the proposed ANN models including multiple soil parameters were then compared with those from the existing empirical equations.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.788-795
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• 2005

In this study, the progressive failure and creep of the traditional ground anchor structure were decreased and a new ground anchor that can attain the required pull-out resistance even in soft sandy soils with low confining pressure was developed. Ground anchors are classified depending on the kind of stress the grout is subjected. 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. The ground anchor that possesses both the tension and compression mechanism mentioned above is known as composition anchor. It is the objective of this study to develope this type of composition anchor. The structure of the newly developed ground anchor was presented. Pull-out test in different types of soil and the behaviour during Pull-out test was also presented.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.286-293
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• 2005

In soft ground the settlement criterion usually governs. Therefore, it is very important not only reasonable assessment of the allowable bearing capacity of the soil but also reasonable assessment of settlement. In the previous studies by many other researchers, load concentration ratio and settlement reduction factor are usually proposed for estimating the settlement of granular compaction piles. In the previous studies, the reinforced ground with granular compaction piles is simplified as composite ground and the analysis is performed with in the basis of this assumption. However, the lateral deformation of granular compaction pile could not be considered and only the relative vertical strength between pile and soils could be considered in the analysis. In this study, a method adapting the Tresca failure criterion is proposed for calculating settlement of granular compaction pile. Proposed method can be considered the strength of pile material, pile diameter, installing distance of pile and the deformation behavior of vertical and horizontal directions of pile. In the presented study, large-scale field load test is performed and the results are described. Also, predictions of settlements from the proposed method are compared with the results of the load test. In addition, a series of parametric study is performed and the design parameters are analyzed.

• Geotechnical Engineering
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• v.14 no.5
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• pp.143-162
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• 1998

In the present study, a procedure to predict the depth from the ground surface to the center of bulging failure zone in each of the square granular group piles under a rigid mat foundation is proposed. This analytical procedure is established on the basis of the conical modeling of bulging failure shape and the replacement ratio of soft foundation soils. considering the effect of a share of procedure to estimate the ultimate cylindrical pressure in the area reinforced with granular piles and the ultimate bearing capacity of each of granular piles in group. This analytical procedure is also established on the basis of the pre-determined depth to the zone of bulging failure and an iterative solution technique. Finally the analytical procedures proposed in this study are verified by analyzing the results of 3D finite element analyses, and the predictions of ultimate bearing capacity of granular piles are compared with the results obtained from the tests, empirical equation and 3D finite element analyses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1814-1819
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• 2010

The relation constant method between OCR and normalized net cone tip resistance has been widely used to estimate OCR value in practice. In this study, the method was analyzed for the soft soils in the Bukmyun area in Changwon city and the northwestern area in Incheon city. The relation constant value was estimated in the range of 0.28~0.33 for the Bukmyun area in Changwon city and 0.49~0.6 for the northwestern area in Incheon city. The value was max. 90% larger than it from the foreign previous studies. This is not the conservative result so the previous methods should be used with great caution of determining the constant value.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.464-475
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• 2009

Electrical resistivity can be used for porosity estimation. In order to improve previously developed ERCP(Electrical Resistivity Cone Probe), 4ERP(4 Electrical Resistivity Probe), which has Wenner array at the tip of probes, has been developed. In properties of current flow Wenner array measures electrical properties of undisturbed area during penetration and relatively correct measurements are guaranteed without polarization. Furthermore, Wenner array equation can estimate electrical resistivity without extra calibration. 4ERP is developed into 2 types, penetration and fixation. Penetration type has wedge-shaped tip. Considering disturbance minimization, fixed type has plane tip. Fixed type 4ERP in consolidation cell measure electrical resistivity increment along porosity decrease, and penetration type 4ERP measured resistivity profile along the depth in chamber. Applying Archie's law, porosity profile was estimated with electrical resistivity. The tests result suggests that 4ERP can be new site investigation equipment with little disturbance.