한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

  • 제36권2호
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  • Pages.5-15
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  • 2020
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  • 1229-2427(pISSN)
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  • 2288-646X(eISSN)
한국지반공학회 (Korean Geotechnical Society)
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개정된 지반증폭계수의 Macro적 액상화 평가에 미치는 영향 분석

Analysis of the Effect of the Revised Ground Amplification Factor on the Macro Liquefaction Assessment Method

  • 백우현 (서울과학기술대학교 건설시스템공학과) ;
  • 최재순 (서경대학교 토목건축공학과)
  • Baek, Woo-Hyun (Dept. of Construction System Engrg., Seoul National Univ. of Science & Technology) ;
  • Choi, Jae-Soon (Dept. of Civil & Architecture Engrg., Seokyeong Univ.)
  • 투고 : 2019.11.19
  • 심사 : 2020.02.20
  • 발행 : 2020.02.29
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초록

포항지진(ML=5.4) 시 발생한 액상화 현상은 국민들에게 지진으로 유발되는 액상화의 위험성을 새롭게 각인시켰고, 이에 대한 대비책으로 액상화 위험지도의 관심이 높아지고 있다. 현재 행정안전부가 보유하고 있는 액상화 위험지도는 2014년 제작된 것으로 전국 100,000개 이상의 시추 자료를 토대로 지하수위 0m인 조건으로 지반조건별 증폭계수를 사용하였으며 시추정보가 없는 지역은 보간법을 이용하여 2km × 2km 격자형식으로 제작된 것이 특징이다. 이러한 가운데, 2018년 행정안전부는 내진설계 공통기준의 새로운 지반분류법과 증폭계수를 공표하였다. 따라서 개정된 행정안전부의 증폭계수를 반영한 액상화 위험지도의 재작성이 필요하다. 본 연구는 내진설계 공통기준 개정 전·후 두 개의 기준으로 전 국토를 대상으로 지반분류를 수행하여 변동성을 분석하였으며, 지반조건별 증폭계수를 적용한 액상화 평가결과를 부산시 강서구를 대상으로 수행하였다. 이때 재현주기 500년과 1,000년에 해당하는 지반가속도를 적용하였으며 우리나라 평균 지하수위인 5m와 극한 조건인 0m로 구분하여 액상화 위험도를 평가하였다. 액상화 위험지도는 기존의 2km × 2km보다 높은 해상도를 확보하기 위해 500m × 500m 격자를 생성하여 위험지도를 작성하였다. 연구결과, 기존 지반분류 기준을 통해 SC, SD 지반으로 분류되었던 지반상태가 개정된 지반분류 기준을 통해 S2, S3, S4로 재분류되었다. 재현주기 500년과 1,000년으로 액상화 평가를 수행한 결과 개정 전 지반증폭계수 적용한 LPI가 상대적으로 과대평가되는 결과를 도출하였다. 본 연구결과는 증폭계수를 이용하는 광역지역 액상화 위험지도 작성의 근간인 액상화 평가에 큰 영향을 미치는 요소로써 향후 광역지역 액상화 위험지도 작성의 경우 반드시 고려될 사항으로 판단된다

The liquefaction phenomenon that occurred during the Pohang earthquake (ML=5.4) brought new awareness to the people about the risk of liquefaction caused by the earthquake. Liquefaction hazard maps with 2 km grid made in 2014 used more than 100,000 borehole data for the whole country, and regions without soil investigation data were produced using interpolation. In the mapping of macro liquefaction hazard for the whole country, the site amplification effect and the ground water level 0 m were considered. Recently, the Ministry of Public Administration and Security (2018) published a new site classification method and amplification coefficient of the common standard for seismic design. Therefore, it is necessary to rewrite the liquefaction hazard map reflecting the revised amplification coefficient. In this study, the results of site classification according to the average shear wave velocity in soils before and after revision were compared in the whole country. Also, liquefaction assessment results were compared in Gangseo-gu, Busan. At this time, two ground accelerations corresponding to the 500 and 1,000 years of return period and two ground water table, 5 m for the average condition and 0 m the extreme condition were applied. In the drawing of liquefaction hazard map, a 500 m grid was applied to secure a resolution higher than the previous 2 km grid. As a result, the ground conditions that were classified as SC and SD grounds based on the existing site classification standard were reclassified as S2, S3, and S4 through the revised site classification standard. Also, the result of the Liquefaction assessments with a return period of 500 years and 1,000 years resulted in a relatively overestimation of the LPI applied with the ground amplification factor before revision. And the results of this study have a great influence on the liquefaction assessment, which is the basis of the creation of the regional liquefaction hazard map using the amplification factor.

키워드

참고문헌

  1. Ahn, J.K., Baek, W.H., Choi, J.S., and Kwak, D.Y. (2018), "Investigation of Pohang Earthquake Liquefaction Using 1D Effective-Stress Site Response Analysis", Journal of the Korean Geotechnical Society, Vol.34, No.8, pp.37-49 https://doi.org/10.7843/KGS.2018.34.8.37
  2. Baek, W. H. (2014), "Development of Real-Time Liquefaction Hazard Map Using Metropolitan Area Site Information Data, University of Seokyeong, Seoul, Korea (in Korean).
  3. Baek, W. H., Choi, J. S., and Ahn, J. K., (2018), "Liquefaction Hazard Map in Pohang Based on Earthquake Scenarios", Journal of Earthquake Engineering Society in Korea, Vol.22, No.3, pp. 219-224 (in Korean). https://doi.org/10.5000/EESK.2018.22.3.219
  4. Cho, H. K., Manandhar, S., and Kim, D. S. (2016), "Site Classification and Design Response Spectra for Seismic Code Provisions- (I) Database and Site Response Analyses", Journal of the Earthquake Engineering Society of Korea, Vol.20, No.4, pp.223-234. https://doi.org/10.5000/EESK.2016.20.4.223
  5. Cho, H. K., Manandhar, S., and Kim, D. S. (2016), "Site Classification and Design Response Spectra for Seismic Code Provisions- (II) Proposal", Journal of the Earthquake Engineering Society of Korea, Vol.20, No.4, pp.235-243. https://doi.org/10.5000/EESK.2016.20.4.235
  6. Cho, H. K., Manandhar, S., and Kim, D. S. (2016), "Site Classification and Design Response Spectra for Seismic Code Provisions- (III) Verification", Journal of the Earthquake Engineering Society of Korea, Vol.20, No.4, pp.245-256. https://doi.org/10.5000/EESK.2016.20.4.245
  7. Choi, J. S., Park, I. J., Hwang, K. M., and Jang, J. B. (2018), "A Study on Seismic Liquefaction Risk Map of Electric Power Utility Tunnel in South-East Korea", Journal of the Korean Geo-Environmental Society, Vol.19, Issue 10, pp.13-19 (in Korean). https://doi.org/10.14481/JKGES.2018.19.10.13
  8. Idriss, I. M. and Sun, J. I. (1997), "User's Manual for SHAKE91", Center for Geotechnical Modeling Department of Civil & Environment Engineering University of California, Davis, C.A., pp.1-11.
  9. Iwasaki, T., Tatsuoka, K., Tokida, F., and Yasuda, S. (1978a), "A Practical Method for Assessing Soil Liquefaction Potential Based on Case Studies at Various Sites in Japan", Proceedings of 2nd International Conference on Microzonation, National Science Foundation UNESCO, San Francisco, C.A., Vol.2, pp.885-896.
  10. Iwasaki, T., Tokida, K., Tatsuoka, F., Watanabe, S., Yasuda S., and Sato, H. (1982), "Microzonation for Soil Liquefaction Potential Using Simplified Methods", Proceedings of 3rd International Conference on Microzonation, Seattle, pp.1319-1330.
  11. Kim, D. S., Lee, S. H., and Yoon, J. K., (2008), "Development of Site Classification System and Modification of Site Coefficients in Korea Based on Mean Shear Wave Velocity of Soil and Depth to Bedrock", Journal of Civil Engineering in Korea, pp.63-74.
  12. Ku, T. J. (2010), "Development of Mapping of Liquefaction Hazard Considering Various Ground Condition in Korea", Master's thesis, Seokyeong University, pp.38-48 (in Korean).
  13. Lee, B. Y., Hwang, B. S., Kim, H, S., and Cho, W. J. (2018), "Precision Improvement Methodology of Geotechnical Information through Outlier Analysis", Journal of the Korean Geo-Environmental Society, Vol.19, No.2, pp.23-35. https://doi.org/10.14481/jkges.2018.19.2.23
  14. Ministry of Construction & Transportation and Earthquake Engineer Society of Korea (1997), "Seismic Design Standard (II)" (in Korean).
  15. Park, D. H., Kwak, D. Y., Jeong, C. G., and Park, T. H. (2012), "Development of Probabilistic Seismic Site Coefficients of Korea", Soil Dynamics and Earthquake Engineering, Vol.43, pp.247-260 (in Korean). https://doi.org/10.1016/j.soildyn.2012.07.018
  16. Sun, C. K. (2010), "Suggestion of Additional Criteria for Site Categorization in Korea by Quantifying Regional Specific Characteristics on Seismic Response", Journal of Korean Society of Earth and Exploration Geophysicists, KSEG, Vol.13, No.3, pp. 203-218 (in Korean).
  17. Sun, C. K., Jeong, C. K., and Kim, D. S. (2005), "A Proposition of Site Coefficients and Site Classification System for Design Ground Motions at Inland of the Korean Peninsula", Journal of Korean Geotechnical Society, KGS, Vol.21, No.6, pp.101-115 (in Korean).
  18. Yoon, J. K., Kim, D. S., and Bang, E. S. (2006), "Development of Site Classification System and Modification of Design Response Spectra Considering Geotechnical Site Characteristics in Korea (I) - Problem Statements of the Current Seismic Design Code", Journal of Earthquake Engineering Society in Korea, Vol.10, No.2, pp. 39-50. https://doi.org/10.5000/EESK.2006.10.2.039