DOI QR코드

DOI QR Code

Seismic Amplification Characteristics of Eastern Siberia

동시베리아 지역의 지진 증폭 특성

  • Park, Du-Hee (Dept. of Civil and Environmental Engrg., Hanyang Univ.) ;
  • Kwak, Hyung-Joo (Dept. of Civil and Environmental Engrg., Hanyang Univ.) ;
  • Kang, Jae-Mo (Korea Institute of Construction Technology) ;
  • Lee, Yong-Gook (Dept. of Civil and Environmental Engrg., Hanyang Univ.)
  • 박두희 (한양대학교 건설환경공학과) ;
  • 곽형주 (한양대학교 건설환경공학과) ;
  • 강재모 (한국건설기술연구원) ;
  • 이용국 (한양대학교 건설환경공학과)
  • Received : 2014.09.17
  • Accepted : 2014.09.29
  • Published : 2014.10.31

Abstract

The thickness of permafrost in Eastern Siberia is from 200 to 500 meters. The seasonally frozen layer can vary from 0 to 4m depending on ground temperature and its location. The shear wave velocity varies from 80m/s in summer to 1500m/s in winter depending on soil type. When melted, large impedence will occur due to the difference between the shear wave velocity of seasonally frozen soil and that of permafrost layer. Large displacement may occur at the boundary of the melted and the frozen layer, and this phenomenon should be considered in a seismic design. In this research, one-dimensional equivalent linear analyses were performed to investigate the effects of the seasonally frozen layer on ground amplification characteristics. Soil profiles of Yakutsk and Chara in Eastern Siberia were selected from geotechnical reports. 20 recorded ground motions were used to evaluate the effect of input motions. As the thickness of seasonally frozen layer and the difference in the shear wave velocity increases, the amplification is shown to increase. Peat, very soft organic soil widely distributed throughout Eastern Siberia, is shown to cause significant ground motion amplification. It is therefore recommended to account for its influence on propagated motion.

동시베리아 지역에 분포하는 영구 동토층의 두께는 평균적으로 200~500m이며, 기온에 따라 지반물성이 변화하는 계절동토층이 지역에 따라 지표면에서 약 0~4m까지 형성되어 있다. 계절 동토의 전단파 속도는 흙의 종류에 따라 여름에는 약 80m/s에서 겨울철 동결상태에서는 약 1500m/s까지 크게 변이한다. 융해시 계절 동토층과 하부의 영구 동토층 사이의 전단파 속도 차이 때문에 매우 큰 임피던스가 발생하고 이로 인해 지진파가 증폭될 수 있다. 특히, 경계면에서 큰 변위가 발생할 수 있으므로 내진설계 시 이의 영향을 고려해야 한다. 본 연구에서는 계절 동토층의 두께와 전단파 속도 변화에 따른 영향이 지반 증폭특성 및 지반변형에 미치는 영향을 규명하기 위하여 1차원 등가정적 지반응답해석을 수행하였다. 동시베리아의 Yakutsk와 Chara 지역에 대한 지질보고서를 바탕으로 지반주상도를 선정하였으며 입력지진파의 영향을 증명하기 위해 총 20개의 계측지진파를 사용하였다. 계절 동토층의 두께가 증가할수록 증폭현상이 크게 발생하였으며, 계절동토층과 영구 동토층 사이의 전단파 속도 차이가 클수록 증폭계수가 증가하는 것으로 나타났다. 특히 동시베리아 지역에 넓게 분포되어 있는 유기질토인 토탄은 증폭에 큰 영향을 미치므로 설계시 이를 반드시 고려해야 할 것으로 판단된다.

Keywords

References

  1. Ahonen, L. (2001), "Permafrost: occurrence and physicochemical processes", Vol.5, Posiva, 2001.
  2. Boulanger, R.W., Arulnathan, R., Harder, L.F., and Torres, R.A. (1998), "Dynamic properties of Sherman Island peat", Journal of Geotechnical and Geoenvironmental Engineering, No.124, Vol.1, 1998, pp.12-20. https://doi.org/10.1061/(ASCE)1090-0241(1998)124:1(12)
  3. Davis, N. (2001), "Permafrost : a guide to frozen ground in transition. Fairbanks, Alaska", University of Alaska press, 2001.
  4. Dunaeva, E.N. and Kondratieva, K.A.(1989), "Seasonal freezing and thawing of soils", Geocryology of the USSR: Middel Siberia, pp.68-71.
  5. FEMA (1997), "NEHRP recommendation provisions for seismic regulations for new buildings and other structures, Part I", pp.337.
  6. Gavrilova, M.K. (1978), "Climate and Long-Term Freezing of Soils", Nauka, Moscow, pp.214.
  7. Ivanov, M.S. (2004), "Cryogenic Structure of Quaternary Deposits of the Lena-Aldan Depression", Novosibirsk: Nauka, pp.126.
  8. KICT (2010), "Development of site investigation and monitoring system for extreme cold region".
  9. Konstantinov, P.Y., Argunov, R.N., Herasimov, E.Y., and Ugarov, I.S. (2008), "The Infleunce of the Winter Season on Active layer Depth in Taiga Landscapes, the Yakutsk Vicinity, East Siberia", the Ninth International Conference on Permafrost, Vol.1, pp.983-986.
  10. Kottke, A.R. and Rathje, E.M. (2008), "Sigma Spectra", University of Texas at Austin, Version alpha, Revision, 2008.
  11. Kottke, A.R. and Rathje, E.M. (2008), "Strata", University of Texas at Austin, Version alpha, Revision, 2008.
  12. Kwak, D. Y., Jeong, C. G., Park, D. H., and Lee, H. S. (2009), "Development of Probabilistic Seismic Coefficients of Korea", JOURNAL OF THE KOREAN GEOTECHNICAL SOCIETY, No.10, Vol.25, pp.87-97.
  13. Leblanc, A.M., Frotier, R., Allard, M., Cosma, C., and Buteau, S. (2004), "Seismic cone penetration test and seismic tomography in permafrost", Canadian geotechnical journal, No.41, Vol.5, 2004, pp.796-813. https://doi.org/10.1139/t04-026
  14. Melnikov, P.I. (1988), "Map of landscapes and permafrost conditions in Yakutia (scale 1:2,500,000)", Permafrost Inst., Siberian Branch, Acad. of Sci. of the USSR, Yakutsk.
  15. Meng, Q., Li, D., Chen, J., Xu, A., and Huang, S. (2008), "Experimental Research on Physical-Mechanical Characteristics of Frozen Soil Based on Ultrasonic Technique", the Ninth International Conference on Permafrost, Vol.2, pp.1179-1183.
  16. MLTM (2009), "Korean Building Code (KBC)", pp.81-85.
  17. Nevskiy, M.V., Zavyalov, A.D., Gliko, A.O., Grachev, A.F., Ulomov, V.I., and Khrometskaya, E.A. (2003), "Presented to the XXIII General Assembly of the International Union of Geodesy and Geophysics, National report", RUSSIAN ACADEMY OF SCIENCES NATIONAL GEOPHYSICAL OMMITTEE.
  18. Qi, J., Ma, W., Sun, C., and Wang, L. (2006), "Ground motion analysis in seasonally frozen regions", Cold Regions Science and Technology, Vol.44, pp.111-120 https://doi.org/10.1016/j.coldregions.2005.09.003
  19. Rathje, E.M., Kottke, A.R., and Trent, W.L. (2010), "Influence of Input Motion and Site Property Variabilities on Seismic Site Response Analysis", Journal of ASCE, Vol.136, pp.617-619.
  20. Romanovsky, V.E., Sazonova, T.S., Balobaev, V.T., Shender, N.I., and Sergueev, D.O. (2007), "Past and recent changes in air and permafrost temperatures in eastern Siberia", Global and Planetary Change, Vol.56, pp.399-413. https://doi.org/10.1016/j.gloplacha.2006.07.022
  21. Sazonova, T.S., Romanovsky, V.E., Walsh, J.E., and Sergueev, D.O. (2004), "Permafrost dynamics in the 20th and 21st centuries along the east siberia transect", Journal of Geophysical Research, Vol.109.
  22. Schnabel, P.B. (1973), "Effects of local geology and distance from source on earthquake ground motions", Ph.D. Thesis, University of Calif., Berkeley.
  23. Seed, H.B., Wong, R.T., Idriss, I.M., and Tokimatsu, K. (1986), "Moduli and damping factors for dynamic analyses of cohesionless soils", Journal of Geotechnical Engineering, Vol.112, No.11, pp.1016-1032. https://doi.org/10.1061/(ASCE)0733-9410(1986)112:11(1016)
  24. Skryabin, P., Varlamov, S., and Skachkov, Y.(2007), "Monitoring of the Thermal Regime of Permafrost in Central Yakutia", Melnikov Permafrost Institute, Siberian Branch of Russian Academy of Sciences, Yakutsk, Russia.
  25. Speker, V.B., Speker, V.B., and Bakulina, N.T. (2008), "New Data on the Ice Complex of the Lena-Amga Rivers Plain (Central Yakutia)", the Ninth International Conference on Permafrost, Vol.2, pp.1681-1684.
  26. Stanilovskaya, J., Ukhova, J., Sergeev, D., and Utkina, I. (2008), "Thermal State of Permafrost in Northern Transbaykalia, Eastern Siberia", the Ninth International Conference on Permafrost, Vol.2, pp.1695-1700.
  27. Suzuki, Y., Hatanaka, M., Ishihara, K., Konno, T., and Akino, K. (1992), "Engineering properties of undisturbed gravel sample", Earthquake Engineering, Tenth World Conference, 1992, Balkema, Rotterdam.
  28. Tsytovich, N., "The Mechanics of Frozen Ground", Translated by Scripta Technical Inc., New York. Published by McGraw-Hill Book Co., New York; 1975.
  29. Vinson, T.S. (1978), "Response of frozen ground to dynamic loadings", Geotechnical Engineering for Cold Regions, McGraw-Hill Book Company; 1978. Chap. 8, pp.405-458.
  30. Wang, D.Y., Zhu, Y.L. Ma, W., and Niu, Y.H. (2006), "Application of ultrasonic technology for physical-mechanical properties of frozen soils", Cold regins Science and Technology, No.44, Vol.1, pp.12-19. https://doi.org/10.1016/j.coldregions.2005.06.003
  31. Wu, Z.W. and Ma, W. (1993), "Strength and Creep of Frozen soil", Lanhou University Press. (In Chinese)
  32. Xu, G., Yang, Z., Dutta, U., Tang, L., and Marx, E. (2011), "Seasonally frozen soil effects on the seismic site response", Journal of Cold Regions Engineering, Vol.25, No.2, June 1, 2011., ASCE, pp.53-70. https://doi.org/10.1061/(ASCE)CR.1943-5495.0000022
  33. Yang, Z.J., Dutta, U., Xu, G., Hazirbaba, K., and Marx, E.E. (2011), "Numerical analysis of permafrost effects on the seismic site response", Soil Dynamics and Earthquake Engineering, Vol.31, No.3, pp.282-290. https://doi.org/10.1016/j.soildyn.2010.08.004
  34. Zimmerman, R.W. and King, M.S. (1986), "The effect of the extent of freezing on seismic velocities in unconsolidated permafrost", Geophysics, Vol.51, No.6, 1986, pp.1285-1290. https://doi.org/10.1190/1.1442181