KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
권호 표지
DOI QR코드

DOI QR Code

Estimation of Shear Wave Velocity of Earth Dam Materials Using Artificial Blasting Vibration Test

인공발파진동실험을 이용한 흙댐 축조재료의 전단파속도 산정

  • Received : 2012.07.31
  • Accepted : 2012.12.26
  • Published : 2013.03.30
Download PDF
⟨ Previous Next ⟩

Abstract

The objective of this study is to estimate shear wave velocity of earth dam materials using artificially generated vibration from blasting events and to verify its applicability. In this study, the artificial blasting and vibration monitoring were carried out at the site adjacent to Seongdeok dam, which is the first blasting test for an existing dam in Korea. The vibrations were induced by 4 different types of blasting with various depths of blasting boreholes and explosive charge weights. During the tests, the acceleration time histories were recorded at the bedrock adjacent to the explosion and the crest of the dam. From frequency analyses of acceleration histories measured at the crest, the fundamental frequency of the target dam could be evaluated. Numerical analyses varying shear moduli of earth fill zone were carried out using the acceleration histories measured at the bedrock as input ground motions. From the comparison between the fundamental frequencies calculated by numerical analyses and measured records, the shear wave velocities with depth, which are closely related to shear moduli, could be determined. It is found that the effect of different blasting types on shear wave velocity estimation for the target dam materials is negligible and the shear wave velocity can be consistently evaluated. Furthermore, comparing the shear wave velocity with the previous researchers' empirical relationships, the applicability of suggested method is verified. Therefore, in case that the earthquake record is not available, the shear wave velocity of earth dam materials can be reasonably evaluated if blasting vibration test is allowed at the site adjacent to the dam.

본 연구의 목적은 인공 발파진동실험을 이용하여 흙댐 축조재료의 전단파속도를 추정하고 산정 방법의 실효성을 확인하는 것이다. 이를 위하여 운영 중인 성덕댐에 대하여 국내 최초로 실대규모 근접 발파진동 실험을 수행하였다. 장약량과 발파 시추공심도를 4가지 유형으로 달리한 발파진동을 유발시키고, 각 유형별 발파 시에 폭원에 인접한 기반암노두와 댐 정상부에서 가속도를 각각 계측하였다. 발파진동실험으로부터 댐 정상부에서 얻어진 계측기록을 주파수 분석하여 대상댐의 고유진동수를 산정하고, 계측된 가속도기록으로 산정한 고유진동수와 기반암에서 계측한 발파파 가속도를 입력하중으로 한 반복적인 동적수치해석을 수행하여 계산한 고유진동수를 일치시키는 방법으로, 흙댐 성토재료의 심도별 전단파속도를 추정하였다. 산정된 대상댐 성토재료의 전단파속도는 발파유형에 영향을 받지 않고 일관성 있는 결과를 산정함을 확인하였고, 기존의 경험적 연구결과와 비교하여 그 실효성도 확인하였다. 이로부터 지진계가 설치되지 않아 실지진 계측기록을 이용할 수 없는 중소규모 댐의 경우, 인접발파에 따른 발파진동계측기록에 대한 분석으로도 댐 축조재료의 전단파속도를 실효성 있게 추정할 수 있음을 확인하였다.

Keywords

References

  1. Ambraseys, N.N. (1960) On the shear response of a two dimensional wedge subjected to an arbitrary disturbance, Bulletin of the Seismological Society of America, Vol. 50, pp. 45-56.
  2. Chopra, A.K. (1995) Dynamics of structures : theory and application of earthquake engineering, Prentice-Hall, Inc., pp. 416-421.
  3. Dowding, C.H. (2000) Construction vibration, 2 nd Edtion, ISBN 0-9644313-1-9, USA, pp. 7-18.
  4. Ha, I.S. and Oh, B.H. (2008) Inverse calculation of shear wave velocity of rockfill zone using microearthquake records, Pro. of Korea Society of Civil Engineers, KSCE, pp. 3051-3054.
  5. Ha, I.S. and Oh, B.H. (2009) Inverse calculation of shear wave velocity of rockfill zone using microearthquake records, Proc. of 29th USSD Annual Meeting and Conference, US Society on Large Dams, Nashville, Tennessee, pp. 465-472.
  6. Hatanaka, M. (1955) Fundamental considerations on the earthquake resistant properies of the earth dam, Bulletin No. 11, Disaster Prevention Research Institute, Kyoto University, Japan (in Japanese).
  7. Itasca Consulting Group (2005) FLAC-Fast Lagrangian Analysis of Continua, Version 5.0, April, Itasca Consulting Group, Inc., Minneapolis, Minnesota.
  8. Kim, N.R. and Ha, I.S. (2012) Evaluation of fundamental period of rockfill dam using blasting vibration test. J. of Korean Society of Civil Engineers, KSCE, Vol.32, No.5C, pp. 185-192 (in Korean). https://doi.org/10.12652/Ksce.2012.32.5C.185
  9. Korean Geotechnical Society(KGS) (2006) Seismic design for earth structures, Series No.8, Goomibooks, pp. 51-197 (in Korean).
  10. Korea Ministry of Land, Transport and Maritime Affairs(MLTM) (2011) Dam design criterion, MLTM, pp. 223-224 (in Korean).
  11. Korea Rural Community Corporation(KRCC) (1983) Design documents for irrigation project of Seongduk province, Korea Rural Community Corporation (in Korean).
  12. Makdisi, F.I. (1976) Performance and analysis of earth dams during strong earthquake, thesis presented of the University of California at Berkeley.
  13. Mejia, L.H. and Seed, H.B. (1983) Comparison of 2-D and 3-D dynamic analyses of earth dams, Journal of Geotechnical Engineering, ASCE, Vol.109, No.11, pp. 1383-1398. https://doi.org/10.1061/(ASCE)0733-9410(1983)109:11(1383)
  14. Sawada, Y. and Takahashi, T. (1975) Study on the material properties and the earthquake behaviors of rockfill dams, Proc. of 4th Japan Earthquake Engineering Symposium, Tokyo, pp. 695-702 (in Japanese).
  15. Schmertmann, J.H. (1970) Static cone to compute settlement over sand, Journal of the Soil Mechanics and Foundations Division, ASCE, Vol. 96, No. SM3, pp. 1011-1043.
  16. Seed, H.B. and Idriss, I.M. (1970) Soil moduli and damping factors for dynamic response analyses, Report No. EERC 70-10, Earthquake Engineering Research Center, Univ. of California Berkeley, California, pp. 1-43.
  17. Vrymoed, J. (1981) Dynamic FEM model of Oroville dam, Journal of Geotechnical Engineering, ASCE, Vol.107, No. 8, pp. 1057-1077.
  18. Yune, J.S. and Park, J.K. (2008) Rock engineering for civil engineers, Goomibooks, pp. 70 (in Korean).

Cited by

  1. Estimation of Shear Wave Velocity of Rockfill Zone by Dynamic Analysis using Micro-earthquake Records vol.35, pp.1, 2015, https://doi.org/10.12652/Ksce.2015.35.1.0141
  2. A review of seismic geophysical testing in Iran for building near-surface velocity models vol.37, pp.1, 2018, https://doi.org/10.1190/tle37010068a1.1