• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.431-438
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• 1999

An assessment of liquefaction potential is made in principle by comparing the shear stress induced by earthquake to the liquefaction strength of the soil. In this study, a modified method based on Seed and Idriss theory is developed for evaluating liquefaction potential. The shear stress in the ground can be evaluated with seismic response analysis and the liquefaction strength of the soil can be investigated by using cyclic triaxial tests. The cyclic triaxial tests are conducted in two different conditions in order to investigate the factors affecting liquefaction strength such as cyclic shear stress amplitude and relative density. And performance of the modified method in practical examples is demonstrated by applying it to liquefaction analysis of artificial zones with dimensions and material properties similar to those in a typical field. From the result, the modified method for assessing liquefaction potential can successfully evaluate the safety factor under moderate magnitude(M=6.5) of earthquake.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1512-1519
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• 2005

In this study, the potential for liquefaction in the Incheon international airport was calculated by appling the standard penetration test data and laboratory test data to the modified Seed & Idriss(2001) method. The analysis was performed on the non-plastic silty layer and silty sand layer which within the depth of 20m, below 20 of the standard penetration value(N), and the ground water level. Also, each set of data was mapped by using GIS(geographic information systems) and the factor of safety for the potential for liquefaction was obtained by overlapping those layers. As a result, it was found that there exist potential hazard zone for the liquefaction partially. So, the additional detailed assessments for those are thought to be necessary.

• Journal of the Society of Disaster Information
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• v.14 no.3
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• pp.296-304
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• 2018

Purpose: This study was carried out to evaluate the liquefaction potential of the land reclamation area in Incheon by using the ProShake program for long frequency Hachinohe seismic wave and short frequency Ofunato seismic waves to interpret ground response. Method: The interpretation results and the Modified Seed and Idriss method were used to evaluate the liquefaction potential. The liquefaction potential index which proposed by Iwasaki was calculated to be used as a guide line to represent the liquefaction evaluation results at the given location. The equivalent liquefaction factor of safety presented by Kang(1999) was used as a quantitative index to draw up the mapping of liquefaction potential. Results: This paper presents the mapping of liquefaction potential for the Incheon seaside reclamation area using both the liquefaction potential index and the equivalent liquefaction factor of safety. Conclution: As a result, the mapping of liquefaction based on the liquefaction potential index and equivalent liquefaction factor of safety shows similar distribution pattern.

• Journal of the Korean GEO-environmental Society
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• v.6 no.2
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• pp.5-14
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• 2005

In the present study, the liquefaction potential in the area of the Incheon international airport was assessed by applying the data of both standard penetration tests and laboratory tests to the modified Seed & Idriss method. The analysis was performed against the non-plastic silty soil layer and silty sand soil layer existing within the depth of 20m and under the ground water level, having the standard penetration value(N) of below 20. Also, each set of data was mapped using the GIS(Geographic Information System) and the safety factor against the liquefaction potential ($FS_{liquefaction}$) was obtained by overlapping those layers. Throughout the analysis, it was found that there exists a potential hazard zone for the liquefaction, showing partially that the safety factor against the liquefaction potential is 1.0 to 1.5 below the standard safety factor criterion. It is further thought to be necessary that the liquefaction potential for the corresponding hazard zone be additionally assessed in detail.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.77-84
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• 1999

An assessment of liquefaction potential is made in principle by comparing earthquake induced shear stress to the liquefaction strength of the soil. In this research a modified method based on Seed and Idriss theory is developed for evaluating liquefaction strength of Jumunjon sand(Korean standard sand). Also the factors affecting liquefaction strenght such as cyclic shear stress amplitude and relative density are investigated and verified by using cyclic triaxial test. From the result the new relationships between cyclic shear stress ratio and number of load cycles are proposed for evaluating liquefaction strength under moderated magnitude(M=6.5) of earthquake.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.431-438
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• 2002

Reclaimed coastal areas for the construction of ports and harbors are in general subjected to strong possibility of liquefaction. In this research, a new method for liquefaction hazard microzonation based on liquefaction settlements was developed. Severity of liquefaction hazard was defined by liquefaction settlements obtained from the method proposed by Tokimatsu and Seed. 10 coastal areas, representing typical geological and geotechnical characteristics of Korean ports and harbors, and 3 real earthquake records for site response analysis were selected. From this research, liquefaction settlement criteria is adapted as a new quantitative index for the liquefaction hazard microzonation. Liquefaction settlements were also compared with LPI (Liquefaction Potential Index), obtained from the assessment of liquefaction potential based on the modified Seed and Idriss's method. As an example, 2 and 3 dimensional liquefaction hazard microzonations of Pusan port and harbor area were mapped by overlapped liquefaction settlement contours.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.141-150
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• 2000

In this study liquefaction hazard potential was assessed by modified Seed and Idriss method and maps of liquefaction hazard potential utilized by LPI(Liquefaction Potential Index) and FE(Equivalent Liquefaction Factor of Safety) were constructed in two dimensional space, Comparisons of liquefaction hazard maps assessed by LPI and FE are represented to verify the FE method proposed in this study. Based on the results of comparing liquefaction hazard map using LPI and FE there is similar distribution trend of zonation indices. from the result of comparison of liquefaction hazard maps of FE base using Hachinohe and ofunato PGA(Peak ground Acceleration) data at one site of port and harbor in Korea the values of FE in liquefaction hazard map using Hachinohe data are underestimated. And in the view of quantitative analysis FE is more convenient than LPI because types of results from FE are factor of safety that widely used in geotechnical practice and aseismic design standard for port and harbor in Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1246-1249
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• 2009

Liquefaction hazard caused by earthquake is the damage in a wide range. Until now, liquefaction hazard potential at a small area or most structure in Korea was assessed by modified Seed & Idriss method. However, it has been known that this method is not proper for metropolitan area due to a lot of time and data to perform the related ground response analyses such as Shake program. For these reasons, the current method has been used facilities or structures, not metropolitan area. In this study, several contents in seismic design of Eurocode and Korean seismic design standard for Port and Harbor were introduced and applied for assessing the liquefaction potential and mapping the liquefaction hazard by LPI(Liquefaction Potential Index). Finally, Ulsan metropolitan city was practically drawn in two dimensional space.