DOI QR코드

DOI QR Code

수침에 따른 공극률이 큰 포항 이암의 특성

Properties of Pohang Mudstone with High Porosity According to Water Immersion

  • 김병수 (한국해양대학교 토목환경공학과) ;
  • 이윤재 (한국해양대학교 토목환경공학과) ;
  • 김태형 (한국해양대학교 토목공학과) ;
  • 김병준 (한국해양대학교 토목환경공학과)
  • Kim, Byung-Soo (Dept. of Civil and Environmental Engrg., Korea Maritime and Ocean Univ.) ;
  • Lee, Yun-Jae (Dept. of Civil and Environmental Engrg., Korea Maritime and Ocean Univ.) ;
  • Kim, Tae-Hyung (Dept. of Civil Engrg., Korea Maritime and Ocean Univ.) ;
  • Kim, Byeong-Jun (Dept. of Civil and Environmental Engrg., Korea Maritime and Ocean Univ.)
  • 투고 : 2021.10.25
  • 심사 : 2021.10.29
  • 발행 : 2021.11.30

초록

본 연구에서는 공극률이 큰 포항지역 이암의 특성을 평가하고자 유효공극률 측정, 전자 현미경(SEM) 관찰 및 X-선 회절분석(XRD), 슬레이킹, 팽창, 수침기간에 따른 일축압축강도 특성을 분석하였다. 16개의 시험편(정육면체, 5cm)에 대한 시험결과, 유효공극률(porosity)은 평균 14.67%로 일반적인 이암 공극률보다 높은 공극률을 보였으며, 전자 현미경(SEM) 관찰을 통해 실제로 공극률이 큼을 확인하였다. X-선 회절분석결과 팽윤성 점토광물 함유량은 2.3~4.1%(녹니석, 카올린)로 선행연구 된 포항지역 이암보다 낮은 점토 함유량을 보였다. 슬레이크 내구성 지수는 37.73~87.73%로 저~중정도 내구성을 보여 선행연구 결과 대비 다소 낮은 내구성을 보였으며, 팽윤성은 30분간 장축방향 최대 흡수팽창 변화률 1.79~1.82%로 급격하게 팽창함을 확인하였다. 수침에 따른 일축압축강도 감소 특성은 수침 10분 경과 후 만에 시험편이 급격히 풍화되어 강도가 감소하여 기존 포항지역 이암과 관련된 선행연구의 결과와도 상이함을 확인하였다. 이것은 연구대상 이암의 큰 공극률 때문으로 판단된다.

In this study, effective porosity measurement, electron microscope (SEM) observation, X-ray diffraction analysis (XRD), slaking, swelling, and unconfined compression strength according to water immersion were analyzed to evaluate the properties of mudstone with high porosity in Pohang. As a result of the test for 16 square samples (5 cm), the effective porosity was 14.67% on average, higher than porosity of general mudstone, and electron microscope observation confirmed that the porosity was actually high. As a result of X-ray diffraction analysis, the swelling clay mineral content was 2.3~4.1%, which was lower than the results of previous studies in Pohang. The slake durability index was 37.73~87.73%, showing low to medium durability, which was lower than the results of previous studies. It was confirmed that the swelling property rapidly expanded to 1.79~1.82% of maximum swelling strain in the major axis direction for 30 minutes. As the properties of decreasing the unconfined compression strength according to water immersion, the samples rapidly weathered after 10 minutes of water immersion, and the strength decreased. It was confirmed that the results of previous studies related to mudstone in Pohang were different. This is judged to be due to the high porosity of mudstone in study.

키워드

참고문헌

  1. Baek, I.W. (2020), "Characteristics of banking structures constructed with improved tertiary mudstone with composite slag and neutralizing and coating agents", Master's Thesis, Korea Maritime & Ocean University.
  2. Baek, I.W., Kim, J.G., Song, Y.S., and Kim, T.H. (2020), "Acid Rock Drainage Generation Capacity of Tertiary Mudstone in Pohang Basin", Journal of Korean Geosynthetics Society, Vol.19, No.2, pp.23-33. https://doi.org/10.12814/JKGSS.2020.19.2.023
  3. Choi, D.L., Kim, S.R., Suk, B.C., and Oh, J.K. (1993), "Shallow Geological Structure of the Yongil Bay, Southeast Coast of Korea", Korean Jour of Petrol. Geol., Vol.1, No.1, pp.53-62.
  4. Franklin, J. and Chandra, A. (1972), "Slake-durability Test", Korean International Journal of Rock Mechanics, Mining Sciences and Geomechanics Abstracts, Vol.9, No.3, pp.325-341. https://doi.org/10.1016/0148-9062(72)90001-0
  5. Gong, J.S., Baek, I.W., Kim, J.G., Song, Y.S., and Kim, T.H. (2021), "A Pilot Test for the Utilization of Road Subsoil of the Tertiary Mudstone in Pohang basin", Journal of Korean Geosynthetics Society, Vol.20, No.3, pp.1-10. https://doi.org/10.12814/JKGSS.2021.20.3.001
  6. Hyundai Engineering (2015), Ground survey report, pp.1-117 (in Korean).
  7. Jung, G.B. (2006), "A study on the geotechnical characteristics and deformation behavior of Pohang's mudstone", Ph.D. Thesis, Yeungnam University.
  8. Jung, Y.T. (1993), "Experimental study on the engineering characteristics of Pohang's mudstone", Master's Thesis, Yeungnam University.
  9. Kim, S.H. (2019), "Evaluation of unconfined compressive strength and durability of cemented weathered mudstone", Master's Thesis, Kyungpook National University.
  10. Ko, E.J. (2013), "A study on the correlation between drying exponent and permeability of rock and cement base specimens", Master's Thesis, Donga University.
  11. Korea Institute of Construction Technology (1990), Ground water management report, pp.9-10 (in Korean).
  12. Korea Land and Housing Corporation (2019), Subsoil investigation report for Pohang Jungang Happy Housing District, pp.4-5 (in Korean).
  13. Lee, J.H. (2020), "Estimation of field application of the soft mudstone for embankment material", Ph.D. Thesis, Andong National University
  14. Lee, S.K., Lee, T.J., and Lee, Y.M. (2012), "Comparison of Effective Porosities Measured by Wet- and Dry-type Vacuum Saturation Methods", Journal of the Korea institute of Mineral and Energy Resources Engineers, Vol.49, No.3, pp.328-337.
  15. Noh, G.M. (2006), "The study of slaking and residual strength of the mudstone", Master's Thesis, Yeungnam University.
  16. Park, J.J. (2015), "Mechanical characteristics of Pohang area mudstone as material for reclamation material", Ph.D. Thesis, Joongbu University.
  17. Park, N.H. (2018), "Strength reduction effect of mudstone by weathering", Master's Thesis, Korea National University of Transportation.