인공 극지환경에 노출된 암석의 동결-융해 풍화특성 = Freeze-thaw Weathering Characteristics of Rock Exposed to Simulated Polar Environment

다국어 초록 (Multilingual Abstract)

Although the interest in polar environment has increased lately, the research in the change of physical properties of rock in these environment, which is essential for construction and maintenance of various building structures and for resource exploration, has been very limited. The artificial freeze-thaw tests in laboratory were performed using simulated geology and climate of the King Sejong Station, Antarctica. Similar rock types around the station, i.e., diorite, basalt, and lapilli tuff in Korea, were used as samples, and artificial freeze-thaw weathering performed from –20°C to +10°C. Using scanning electron microscopy and X-ray computed tomography, the change of microstructure was investigated: particle detachment, crack initiation and propagation. The changes of physical properties including linear decreases of P- and S-wave velocity and dry weight were also analyzed. The rock with high porosity, low tensile strength, and loose structure was susceptible to freeze-thaw eathering. The laboratory test methods and analysis techniques suggested in this research can be applied to further rock weathering assessment and the results are expected to be used to predict the behavior of rocks in cold regions.

국문 초록 (Abstract)

최근 들어 극지환경에 대한 관심이 증대되고 있지만 건축물 건설 및 유지보수, 자원탐사 등에 필수적인 극지환경에서의 암석의 물리적 변화에 관한 연구는 부족한 실정이다. 본 연구는 남극 세종과학기지의 지질 및 기후환경을 모사하여 실험실에서 인공 동결-융해 시험을 수행하였다. 기지 주변의 주요암종과 동일한 암종인 섬록암, 현무암, 응회암을 국내에서 채취하여, - 20°C 에서 동결시키고 + 10°C에서 융해시키는 인공풍화를 수행하였다. 시험 중 일정 주기마다 주사전자현미경과 X선 단층촬영 영상을 취득하여 미세구조의 변화를 관찰한 결과 모든 시료에서 입자탈락, 균열의 생성 및 확장이 관찰되었으며, 탄성파속도와 건조무게를 측정하여 물리적 특성의 변화를 관찰한 결과 탄성파속도와 건조무게가 선형적으로 감소하였다. 높은 공극률, 낮은 인장강도, 느슨한 구조를 가지는 암석일수록 동결-융해 풍화에 취약한 것으로 나타났다. 본 연구는 암석의 미세구조 및 물리적 특성에 대한 실내실험 기법을 제안함으로써 향후 암석의 풍화 분석에 이용될 수 있으며, 연구결과는 저온지역 암석의 거동 예측에 이용될 수 있을 것으로 기대된다.

참고문헌 (Reference)

1 조태진, "풍화진행에 따른 한라산조면암의 역학적 특성변화" 한국암반공학회 19 (19): 287-303, 2009

2 엄정기, "동결-융해 풍화에 의한 원주지역 쥬라기 화강암의 지질공학적 특성변화" 대한자원환경지질학회 42 (42): 261-272, 2009

3 박연준, "동결-융해 시험에 의한 화강암의 풍화 특성 연구" 한국암반공학회 13 (13): 215-224, 2003

4 박지환, "남극 세종기지의 기후 환경을 모사한 암석의 동결-융해 풍화 시험" 한국자원공학회 47 (47): 731-742, 2010

5 Bland, W., "Weathering: An Introduction to the Scientific Principles" Arnold 87-92, 1998

6 Park, J.D., "Variation of Physical Properties of Rocks Subject to Artificial Weathering" 17 : 51-60, 2003

7 Carlson, W. D., "Three-dimensional imaging of earth and planetary materials" 249 : 133-147, 2006

8 Wright, J.S., "The spalling of overgrowths during experimental freeze-thaw of a quartz sandstone as a mechanism of quartz silt production" 31 : 631-638, 2000

9 Hall, K., "The role of thermal stress fatigue in the breakdown of rock in cold regions" 31 : 47-63, 1999

10 Walder, J.S., "The physical basis of frost weathering: toward a more fundamental and unified perspective" 18 (18): 27-32, 1986

11 Tsytovich, N.A., "The Mechanics of Frozen Ground" McGraw-Hill 426-, 1975

12 Simonsen, E., "Thaw weakening of pavement structures in cold regions" 29 : 135-151, 1999

13 KSRM, "Standard Test Method of Rock"

14 Grossi, C. M., "Predicting long term freeze-thaw risks on Europe built heritage and archaeological sites in a changing climate" 377 : 273-281, 2007

15 Nicholson, D.T., "Physical deterioration of sedimentary rocks subjected to experimental freeze-thaw weathering" 25 : 1295-1307, 2000

16 Davis, N., "Permafrost: A Guide to Frozen Ground in Transition" University of Alaska Press 351-, 2001

17 Irfan, T. Y., "Mineralogy, fabric properties and classification of weathered granites in Hong Kong" 29 : 5-35, 1996

18 Matsuoka, N., "Mechanisms of rock breakdown by frost action: an experimental approach" 17 : 253-270, 1990

19 Tan, X., "Laboratory investigations on the mechanical properties degradation of granite under freeze-thaw cycles" 68 : 130-138, 2011

20 Kim, H., "Geochronologic evidence for early cretaceous volcanic activity on Barton Peninsula, King George Island, Antarctic" 19 : 251-260, 2000

21 Potts, A.S., "Frost action in rocks: some experimental data" 49 : 109-124, 1970

22 Waltham, T., "Foundations of Engineering Geology" Tayler & Francis 30-31, 2009

23 Fujun, N., "Field experiment study on effects of duct-ventilated railway embarkment on protecting the underlying permafrost" 45 : 178-192, 2006

24 Marco Castaño, L.D., "Failures in the standard characterization of carbonate dimension stone durability during freeze-thaw testing" 1-5, 2010

25 Chen, T. C., "Effect of water saturation on deterioration of welded tuff due to freeze-thaw action" 38 : 127-136, 2004

26 Yavuz, H., "Effect of freeze-thaw and thermal shock weathering on the physical and mechanical properties of an andesite stone" (70) : 2-, 2010

27 Dewanckele, J., "Contributions of X-ray CT to the characterization of natural building stones and their disintegration" 164-171, 2010

28 Ruiz de Argandoña, V.G., "Characterization by computed X-ray tomography of the evolution of the pore structure of a dolomite rock during freeze-thaw cyclic tests" 24 (24): 633-637, 1999

29 Gautier, D. L., "Assessment of undiscovered oil and gas in the Arctic" 324 : 1175-1179, 2009

30 Hall, K., "Antarctic rock weathering simulations: simulator design, application and use" 1 : 45-50, 1989

31 KOPRI, "Annual Weather Report: King Sejong, Korean Antarctic Station(2005-2006)" KOPRI 95-178, 2007

32 Davidson, G.P., "A photoelastic study of ice pressure in rock cracks" 11 : 141-153, 1985

33 Kim, S.S., "A Study on the Change of Rock Properties using Artificial Weathering Test" 36 : 141-149, 1999