DOI QR코드

DOI QR Code

Effect of Loading Frequency Dependent Soil Behavior on Seismic Site Effect

하중의 주파수에 의하여 지배받은 흙의 동적 거동이 부지증폭현상에 미치는 영향

  • Park Du-Hee (Dept. of Civil Engrg., Hanyang Univ.) ;
  • Hashash Y.M.A (Dept. of Civil & Environmental Engrg., Univ. of Illinois at Urbana-Champaign) ;
  • Lee Hyun-Woo (Graduate Student., Dept. of Civil Engrg., Hanyang Univ.) ;
  • Kim Jae-Yoen (Graduate Student., Dept. of Civil Engrg., Hanyang Univ.)
  • Published : 2006.03.01

Abstract

Equivalent linear analysis is widely used in estimating local seismic site effects. The soil behavior in the analysis is often assumed to be rate-independent and is not influenced by the seismic loading frequency. Laboratory results, however, indicate that cohesive soil behavior is greatly influenced by the loading frequency. A new equivalent linear analysis method that accounts for the loading frequency dependent soil behavior is developed and used to perform a series of one dimensional site response analyses. Results indicate that while frequency dependent shear modulus has limited influence on computed site response, frequency dependent soil damping greatly filters out high frequency components of the ground motion and thus results in lower response.

등가선형해석은 지반증폭현상을 모사하기 위하여 널리 사용되고 있으며, 해석 시 흙의 거동은 하중의 주파수의 영향을 받지 않는다고 가정되어왔다. 반면, 실내시험은 점성토의 경우 하중의 주파수의 영향을 크게 받는다는 것을 보여주고 있다. 본 연구에서는 하중의 주파수가 흙의 동적 거동에 미치는 영향을 고려하는 새로운 등가선형해석기법이 개발되었으며 주파수의 영향을 규명하기 위하여 지반응답해석을 수행하였다. 해석 결과, 하중의 주파수에 따라서 변화하는 전단탄성계수가 지반응답에 미치는 영향은 작은 반면 감쇠비는 큰 영향을 끼치는 것으로 판명되었다. 이는 하중의 주파수가 높아질수록 흙의 감쇠비도 같이 증가하며 이로 인하여 지진파의 고주파수 요소가 필터링 되기 때문이다. 따라서, 하중의 주파수에 지배 받는 흙의 거동은 특히 고주파수 요소가 풍부한 지진파 전파 모사 시 특히 중요하다고 판단된다.

Keywords

References

  1. Boore, D. M. (2000), SMSIM FORTRAN program for simulating ground motions from earthquakes: Version 2.0. A revision of OFR 96-80-A, OF 00-509, US Geological Survey
  2. EPRI. (1993), Guidelines for determining design basis ground motions, EPRI TR-102293, Electric Power Research Institute, Palo Alto, CA
  3. Frankel, A. M., C. Perkins, D. Barnhard, T. Leyendecker, E. Safak, E. Hanson, S. Dickman, N. Hopper, M. (1996), National seismic hazard maps: Documentation June 1996, OFR 960532, US Geological Survey
  4. Hashash, Y. M. A. and Park, D. (2001), 'Non-linear one-dimensional seismic ground motion propagation in the Mississippi embayment', Engineering Geology, Vol.62, No.1-3, pp.185-206 https://doi.org/10.1016/S0013-7952(01)00061-8
  5. Hashash, Y. M. A. and Park, D. (2002), 'Viscous damping formulation and high frequency motion propagation in non-linear site response analysis', Soil Dynamics and Earthquake Engineering, Vol.22, No.7, pp.611-624 https://doi.org/10.1016/S0267-7261(02)00042-8
  6. Idriss, I. M. (1990), 'Response of Soft Soil Sites During Earthquakes', Proc. of the Symposium to Honor H.B. Seed, Berkeley, CA, pp.273-289
  7. Isenhower, W. M. and Stokoe, K. H. (1981), 'Strain-rate dependent shear modulus of San Francisco Bay Mud', Proc. of International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, University of Missouri-Rolla, pp.597-602
  8. Kim, D. S., Stokoe, K. H., and Hudson, W. R (1991), Deformational characteristics of soils at small to intermediate strains from cyclic tests, Research Report 1177-3, University of Texas at Austin, Austin, TX
  9. Kramer, S. L. (1996), Geotechnical earthquake engineering, Prentice Hall, Upper Saddle River, N.J, pp.254-275
  10. Laird, J. P., and Stokoe, K. H. (1993), Dynamic properties of remolded and undisturbed soil samples test at high confining pressure, GR93-6, Electric Power Research Institute
  11. Matesic, L. and Vucetic, M. (2003), 'Strain-rate effects on soil secant shear modulus at small cyclic strains', Journal of Geotechnical and Geoenvironmental Engineering, Vol.129, No.6, pp.536-549 https://doi.org/10.1061/(ASCE)1090-0241(2003)129:6(536)
  12. Olson, R. E. and Parola, J. F. (1967), 'Dynamic shearing properties of ocmpacted clay', Proc. of International Symposium on Wave Propagation and Dynamic Properties of Earth Materials, Albuquerque, N.M., pp.173-182
  13. Park, D. (2004), Estimation of non-linear seismic site effects for deep deposits of the Mississippi Embayment, Mid America Earthquake Center CD Release 04-06, Urbana
  14. Park, D. and Hashash, Y. M. A. (2004), 'Soil damping formulation in nonlinear time domain site response analysis', Journal of Earthquake Engineering, Vol.8, No.2, pp.249-274 https://doi.org/10.1142/S1363246904001420
  15. Richardson, A. M. and Whitman, R. V. (1963), 'Effect of strain-rate upon undrained shear resistance of a saturated remoulded fat clay', Geotechnique, Vol.13, No.4, pp.310-324 https://doi.org/10.1680/geot.1963.13.4.310
  16. Rix, G. J. and Meng, J. W. (2005), 'A non-resonance method for measuring dynamic soil properties', Geotechnical Testing Journal, Vol.28, No.1, pp.1-8
  17. Schnabel, P. B., Lysmer, J. L., and Seed, H. B. (1972), SHAKE: A computer program for earthquake response analysis of horizontally layered sites, EERC-72/12, Earthquake Engineering Research Center, Berkeley, CA
  18. 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)
  19. Vucetic, M. and Dobry, R. (1991), 'Effect of soil plasticity on cyclic response', Journal of Geotechnical Engineering, Vol.117, No.1, pp.87-107
  20. Whitman, R. V. (1957), 'The behaviour of soils under transient loadings', Proc. of 4th International Conference on Soil Mechanics and Foundation Engineering, London, pp.207-210
  21. Yong, R. N. and Japp, R. D. (1967), 'A flow law for clays in dynamic compression', Proc. of International Symposium on Wave Propagation and Dynamic Properties of Earth Materials, Albuquerque, N.M., pp.183-188