• Geophysics and Geophysical Exploration
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• v.8 no.2
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• pp.177-183
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• 2005

The subject of this paper is research into the application of electrical resistivity monitoring to detecting the water leakage of water utilization facilities. For this purpose, we installed a comprehensive monitoring system consisting of resistivity measurement, inclinometer, piezometer, and water gauge at an embankment. Using this monitoring system, we monitored the various kinds of measurement data and compared the resistivity structures and that of hydrological and engineering data in order to investigate the water leakage and stability of the embankment. The variant images of electrical resistivity at the embankment were provided from the monitoring data and we could accurately locate the portion of which resistivities have sharply changed. Furthermore, we could estimate the stability of the embankment more effectively and quantitatively by jointly interpreting the monitoring data of resistivity, water level, pore water pressure, and subsurface displacement. The monitoring experiments in this study led us to the conclusion that for the efficient maintenance of the water utilization facilities, monitoring the resistivity data and hydrological data would be much more preferable to performing the just one-time measurements.

• Geotechnical Engineering
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• v.10 no.1
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• pp.19-26
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• 1994

In this paper, the application of the rock classification method based on indicator kriging and the cost of errors, which can incorporate qualitative data, was presented. In particular, the binary classification of rock masses was considered. To this end, a simplified RMR system was used. Since most of subjectivity in this analysis occur during the estimation of loss functions, a sensitivity analysis of loss functions was performed. Through this research, it was found out that an expected cost of errors could successfully be used as an indication for how well a sampling plan was designed. In certain conditions, qualitative data can be more economical than quantitative data in terms of expected costs of errors and sampling costs. Therefore, an additional sampling should be carefully determined depending upon the surrounding geologic conditions and its sampling cost. The application method shown in this paper can be useful for more systematic rock classifications.

• Journal of the Korean Geotechnical Society
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• v.32 no.3
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• pp.5-13
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• 2016

Stability analysis was conducted to analyze the application of pile-supported embankment to concrete slab track on the soft ground in Korea. Pile efficiency and tension of geosynthetics in accordance with the hight of embankment and the depth of soft soil were carried out by theoretical and numerical methods. Theoretical method predicted more conservatively than the numerical method for all the cases presented herein. The settlement stability is satisfied to allowable criteria of high speed railway in Korea. The pile-supported embankment has great potential for application to soft ground condition.

• Journal of the Korean Geotechnical Society
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• v.36 no.8
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• pp.27-34
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• 2020

Strong alkaline waste water is generated in large quantities due to using Concrete, shotcrete and various compounds in tunnel construction sites. As the release of this alkaline waste water will contaminate the stream water, it has to be neutralized. Currently, this waste water is mainly neutralized by using sulfuric acid or hydrochloric acid, but the risks of corrosion and handling of facilities are inherent and the chemical control act requires strict management measures. Therefore, using CO₂ (carbon dioxide) as an alternative has been highlighted and various indoor experiment studies have been conducted to prove its potential. However, it is difficult to apply CO₂ to the site because it is still completely lacking in field application research and shows different characteristics from indoor experiments. In this study, the actual site applicability is verified through field testing.

• Journal of the Korean Geotechnical Society
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• v.20 no.1
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• pp.21-27
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• 2004

In this test, there was two-dimensional model loading test implemented for analysis with respect to the problem of evaluating bearing capacity and the application range on the dredged and reclaimed ground, so it was possible to get the following result by comparing a result of loading test and an equation proposed previously. When the difference between average undrained shea. strength by (equation omitted)B of loading board width and the strength under. (equation omitted)B is mere than $\pm50%$, the applicability of Nc(coefficient of bearing capacity where $\phi=0$ analysis is considered in the single layer) was declined. As well, using Nc=5.7, 5.14(coeffcient of bearing capacity where $\phi=0$ analysis is applicable to saturated clay without special limit) for evaluating bearing capacity on the dredged and reclaimed ground causes poor applicability, therefore that seem to be applicable when water content is less than about 75% which makes the unconfined compression test possible.

• Journal of the Korean Geotechnical Society
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• v.28 no.12
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• pp.17-25
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• 2012

FEM requires the stress-strain relationship equations for numerical analyses. However, most formulations for the stress-strain relationship published up to the present are not satisfactory enough to properly express all the levels from the small strain to the peak. Tatsuoka and Shibuya (1991) suggested a new single formulation applicable not only to a wide range of geo-materials from soft clay to soft rock, but also to a wide range of strain levels from $10^{-6}$ to $10^{-2}$. The plain strain compression test is carried out to seven samples of research standard sand specimens and two samples of glass beads, which have been used at world-renowned research institutes. In this study, strains of the maximum principal stress (${\sigma}_1$) and the minimum principal stress (${\sigma}_3$) were thoroughly measured from $10^{-6}$ to $10^{-2}$, and the result, applied to Tatsuoka and Shibuya's new formulation, coincided closely with the measured data of the stress-strain relationship from the small strain to the peak.

• Journal of the Korean Geotechnical Society
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• v.35 no.10
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• pp.67-78
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• 2019

The efficiency of suppressing fine dust was evaluated by conducting indoor and field experiments for the ground treated with EICP solution, which is an eco-friendly ground improvement method. In laboratory experiments, the EICP solution was prepared with inexpensive materials for the field applicability, and the optimal mixing ratio and optimal spraying volume of EICP solution were calculated. The optimum amount of calcium carbonate was shown when the ratio of urea/calcium chloride and white powder were 1.5 and 15 g/L, respectively. The optimum spraying amount of the EICP solution was $7L/m^2$ determined by fine dust suppression and cone tip resistance experiments. The spraying of water and EICP solution was conducted at the test-bed where dump trucks pass for the effect of suppressing fine dust of each method. The effective fine dust suppression method can be chosen depending on the situation of the site.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.99-106
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• 2020

Man-made slope is inevitable to make a new road, which may result in environmental problems as well as collapse of slope. To prevent these problems, various methods such as geogrid reinforced retaining wall, precast concrete-panel retaining wall, and so on, have been introduced and developed. Among these methods, this paper presents the evaluation of field application of precast concrete-panel retaining wall attached to in-situ ground (so called top-down) compared to the conventional construction method of precast concrete-panel retaining wall (so called bottom-up) through the field test and numerical analysis. As a result, the safety factor of both methods in final stage is similar, however, top-down method guarantees the slope stability during the construction compared to bottom-up method.

• Journal of the Korean Geotechnical Society
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• v.22 no.5
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• pp.69-81
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• 2006

The micropile, which is a kind of the in-situ manufactured pile with small diameter of $150\sim300mm$, is constructed by installing a steel bar or pipe and injecting grout into a borehole. The application fields of micropile are being gradually expanded in a limited space of down-town area, because the micropile has various advantages with low vibration and noise in method and compact size in machine, etc. Mostly, the micropile has been applied to secure the safety of structures, depending on the increment of bearing capacity and the restraint of displacement. The micropile is expected to be used in various fields due to its effectiveness and potentiality in the future. The model test, focused on the interaction between micropile and soil in this study, was carried out. The micropile is installed in a soil adjacent to footing (concept of 'soil reinforcement'). With the test results and soil deformation analysis, the reinforcement effect (relating to bearing capacity and settlement) was analysed in a qualitative and quantitative manner, respectively. Consequently, it is expected that we nay demonstrate the improvement of an efficiency and application in the design and construction of micropile.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.23-36
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• 2007

To overcome the limits of the static pile load test for large diameter drilled shafts, bi-directional low pressure pile load test (BDL PLT) has been used but this test method containes some problems that has not been solved basically. That is, BDL PLT has some problems: difficulty in jack (or cell) arrangement for large test capacity, void remain inside jack (or cell) due to the unrecovery of piston after test etc. In this study, bi-directional double-acting high pressure pile load test (BDH PLT W/DOJ) was developed and confirmed for a in-situ large diameter drilled shaft. At present, test specification of bi-directional pile load test (BDPLT) is being made, and severed main issues (such as, test kinds, test capacity, necessity of use of double-acting and attention of application to service pile) will be contained at the specification.