• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.65-73
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• 2006

Reliability between safety factor and reliability index for driven and bored pile load capacity was analyzed in this study. 0.1B, Chin, De Beer, and Davisson's methods were used for determining pile load capacity by using load-settlement curve from pile load test. Each method defines ultimate yield and allowable pile load capacities. LCPC method using CPT results was performed for comparing results of pile load test. Based on FOSM analysis using load factors, it is obtained that reliability indices for ultimate pile load capacity were higher than those of yield and allowable condition. Present safety factor 2 for yield and allowable load capacities is not enough to satisfy target reliability index $2.0{\sim}2.5$. However, it is sufficient for ultimate pile load capacity using safety factor 3.

• Journal of the Korean Geotechnical Society
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• v.25 no.8
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• pp.33-45
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• 2009

The conventional single-core PBDs have been widely used in order to accelerate consolidation settlement of soft grounds. When using the single-core PBD in a thick clay deposit, a delay of consolidation may occur due to high confining pressure in the thick deposit and necking of drains. This study is to compare the performances of soil improvement by the single-core and double-core PBD installed at a site in Busan New Port which exhibits approximately a 40m-thick clay layer. An in-situ test program was performed at the test site where a set of the double-core PBDs and single-core PBDs were installed to compare the efficiency of each drain. In addition, the discharge capacity of each PBD has been measured using the modified Delft Test. A series of laboratory tests for estimating in-situ soil properties have also been performed in order to obtain input parameters for a numerical program ILLICON. The discharge capacity of the double-core PBD is higher than that of the single-core PBD in the modified Delft Test. However it is observed from the comparative in-situ test and numerical analysis that there is no difference in the performance of ground improvement between the two drain systems. This discrepancy comes from the fact that the amount of water released during consolidation in most common field conditions is much smaller than the capacity of even the single core PBD. And thus, considering actual field conditions, it can be concluded that the single-core PBD has enough discharge capacity even in the thick clay deposit such as this test site.

• Journal of the Korean Geotechnical Society
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• v.26 no.1
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• pp.5-19
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• 2010

Geo-layer information is important to determine pile length and estimate residual settlement in the construction site. An overall spatial distribution of geo-layers in the entire construction site can be predicted using drill-log information. In this study, the geo-layer distribution at Song-do area was estimated by kriging and inverse distance weighting methods, and a cross validation was adopted to verify the reliability of estimation results. The analysis results indicate that the best fitted theoretical variogram model to the experimental variogram does not always provide the most reliable estimation in the kriging method. The proper $\alpha$ value of inverse distance weighting method must be determined by types of geo-layer, because the $\alpha$ value is affected by types of geo-layer. Results of the kriging method show more reliable results than those of inverse distance weighting method, and the structure of geo-layer distribution could be evaluated by variogram in the kriging method.

• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.23-37
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• 2007

Recently a concept of pile-tip enlarged PHC pile (Ext-PHC pile), for use in the auger-drilled construction method, has been developed and is being implemented in practice. A series of field axial load tests on both PHC and Ext-PHC piles were conducted at an experimental site. In addition, a parametric study on a number of influencing factors was made using a validated finite element model. The field axial load tests indicated an enhanced load-settlement characteristics for the Ext-PHC piles compared with the PHC piles, giving approximately 50% increase in the end bearing capacity. Also found in the results of the parametric study was that the increase in the end bearing capacity of Ext-PHC piles slightly varies with the mechanical properties of supporting ground as well as pile length, in the range of 1.25 to 1.4 time that of PHC. Overall, the results of the field tests as well as the numerical study confirmed that the end bearing capacity of PHC pile can be improved by the concept of.Ext-PHC pile.

• Korea Trade Review
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• v.43 no.3
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• pp.101-124
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• 2018

After the establishment of the Korean Product Liability Act, a new clause on the burden of proof has been added and is being revised to meet the purpose of consumer protection. Article 3(2) of the new clause stipulates a provision for estimating a causal relationship when proving indirect facts to alleviate burden of proof. While consumer rights are increasing and public attention is drawn to consumer issues, problems are still emerging. In order to solve the problem, the U.S. Product Liability Act, which has strong consumer rights, was examined to describe the direction in which Korea's Product Liability Act should proceed in terms of consumer protection. The results of the comparative analysis show that the US has expanded the concept of strict liability in terms of rigorous liability, consumer dispute resolution, provable possibility, and litigation accessibility, The consumer dispute settlement system has thoroughly protected consumers by operating educational and systemic consumer ADR system. As for the possibility of proving, Korea has three provenances, and the United States has one. In the United States, where consumer lawsuits are frequent, lawsuits are more accessible than those in Korea, where the party responsible for proving is turned into a manufacturer and responsible for proving the case. This study focuses on consumer protection and provides implications for Korean product liability law.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.6
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• pp.875-885
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• 2018

This study analyzed the major issues of the Candlelight Rally and Taegukgi Rally registered in news comments of the politics section of the portal site from October 24, 2016 to March 19, 2017. We examined the political recognition of the two rallies with the Named Entity Recognition. The main analytical items are the responsibility for impeachment, the subject and method of settlement, and other major issues. As a result of the analysis, the comments of the Candlelight Rally focused on the impeachment support and the legal penalties of the regime ministers, and insisted on resolving the political situation through the next election after impeachment. The comments of the Taegukgi Rally focused on the rejection of the impeachment to maintain the regime and insisted on rejecting the impeachment of the Constitutional Court. The conflicts between the group that supported Candlelight Rallis and the group that supported Taegukgi rallies are predicted to last at least for the time being (Park Geun-hye's trial period) after the presidential election. After the impeachment of the President and replacement of the regime this conflict will develop into the confrontation between the pursuit of liquidation and new politics and the attempt to influence the trial of Park Geun-hye. Therefore, the efforts to integrate society in the aftermath are necessary.

• Journal of the Korean Geotechnical Society
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• v.39 no.7
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• pp.69-76
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• 2023

Cavity causes settlement and its remediation after an accident results in significant time and economic losses. This study aims to experimentally evaluate the prospect of using infrared camera to detect and measure underground subsidence. Emissivity is necessary to detect the energy emitted from an object and accurately assess temperature using an infrared camera. The emissivity in laboratory tests is fixed to evaluate a reasonable distance between the infrared camera and the object, and temperature values are assessed at various distances. In field experiments, the cavity of the field experiment is simulated using a PVC pipe with a diameter of 5 cm, artificially buried at depths of 5 and 25 cm from the surface. The infrared camera measurements are taken from 4 PM to 3 PM of the next day (a total of 23 h). The analysis included the time-series temperature distribution and the cooling rate index assessment, which represents the temperature change rate per unit of time. The results showed that various temperature trends are observed depending on the location of the subsidence. This study demonstrates that the infrared camera can be used to assess the condition of the subsurface.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6C
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• pp.321-329
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• 2008

In this study, a series of column test as a way in order to make up for the weakness point of the conventional acceleration method were conducted to both propose the suction board drain method and grapes the specific improvement character of this method as a result of a sort of plastic drain board and a phase of vacuum pressure conditions. On this occasion, the study focused on computing the effective factors of the fittest Suction board drain method affected by each condition through confirming the settlement generated during the test, the water content reduction and stress increase effect occurred arising from the test, and the ratio of consolidation related to the improvement period. In accordance with the shape of core and that whether the core is attached to the filter(pocket or adhesion), the castle type of adhesion and the column type of pocket are more efficient than the others as a consequence of the test to find out the improvement effect depending on each drainage such as a castle type, coil type, harmonica type, column type of pocket and a castle of the adhesion. In case of the step suction pressure, the shorter the period of $-0.8\;kg/cm^2$ as a final step of the suction pressure is, the better the improvement is. In addition, the correlation between degree of consolidation per each suction pressure level and duration of application was drawn as a curve and the point of inflection on this curve was provided to determine the duration period to maximize the consolidation.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.122-138
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• 2023

Today, fishing villages are on the verge of extinction due to severe aging within the population and outward migration. Recent projects and studies targeting fishing villages viewed the fishing villages from an outsider-centered perspective, without a local-centered understanding of the village as a daily living space. Therefore, to understand the settlement environment of fishing villages, this study analyzed empirical data on the usage behavior of fishing village residents to gain insight into the characteristics of the outdoor space uses of residents in fishing villages. In this regard, a face-to-face survey was conducted among residents, and a village map drawn by the villagers showedthe spatial perception of the villagers. Empirical data on the behavior of fishing villagers using the village space was collected and analyzed through GPS. The study results suggested that residents of fishing villages tend to focus on productive activities, such as fishing, leading to a lack of awareness of other leisure activities and spaces. This monotonous pattern of space utilization within the village appears to stem from an absolute lack of available facilities within the target area. Therefore, in future village regeneration projects aimed at improving the quality of life for residents in fishing villages, it is essential to consider the residents' perception and utilization of space as a priority. The results of this study can be considered valuable foundational data for understanding the utilization of spaces within fishing villages and can be effectively utilized in planning initiatives to enhance quality of life.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.407-419
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• 2006

Situations where support is provided solely in shaft resistance of drilled shafts are where the base of the drilled hole cannot be cleaned so that it is uncertain that any end bearing support will be developed. Alternatively, where sound bed rock underlies low strength overburden material, it may be possible to achieve the required support in end bearing on the rock only, and assume that no support is developed in the overburden. However, where the drilled shaft is drilled some depth into sound rock, a combination of side wall resistance and end bearing can be assumed. Both theoretical and field studies of the performance of rock socketed drilled shafts show that the major portion of applied load is usually carried in side wall resistance. Normal stress at the rock-concrete interface is induced by two mechanisms. First, application of a compressive load on the top of the pile results in elastic dilation of the concrete, and second, shear displacement at the rough surface of the drilled hole results in mechanical dilation of the interface. If the stiffness of the material surrounding the socket with respect to normal displacement is constant, then the normal stress will increase with increasing applied load, and there will be a corresponding increase in the shear strength. In this study, the numerical analyses are carried out to investigate the behavioral characteristics of side of rock socketed drilled shafts. The cause of non-linear head load-settlement relationship and failure mechanism at side are also investigated properly and the design charts are suggested and verified for the leading to greater efficiency and reliability in the pile design.