Journal of the Korean Geographical Society (대한지리학회지)

The Korean Geographical Society (대한지리학회)
권호 표지

A Study on Relationship between Point Load Strength Index and Abrasion Rate of Sediment Particle

퇴적물 입자의 점하중강도지수와 마식율의 관계에 대한 연구

  • Published : 2008.12.31
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Abstract

Sediment abrasion in rivers is caused by the interaction between bedrock channel bed and sediment particles transported through the river. Abrasion rate of sediment particles in rivers is controlled by two major factors; Sediment transport conditions including hydraulic conditions form the erosive forces and physical and chemical strengths of the particles form a resistance force against abrasion and other erosional processes. Physical experiments were performed to find the role of each variable on sediment abrasion process. Total 266 sediment particles were used in this experiment. All sediment particles were divided into 11 independent sediment groups with sediment particle size and sediment loads. Each sediment groups were abraded in tumbling mill for up to 8 hours. Changes in weight were recorded by run and total: 2,128 cases of abrasion rate were recoded. Physical strength of rock particles was measured with point load strength index. It is found that sediment abrasion rate has a negative functional relationship point load strength index ($I_{a(50)}$) ($R^2=0.22$). It was suggested that physical strength of sediment particles set the "maximum possible abrasion rate'. As sediment flux increases, abrasion rates of sediment particles with similar point load strength index were changed. It could be concluded that not only physical characteristics of sediment particles, but also sediment transport conditions control sediment abrasion rates.

하천 퇴적물질의 마식은 하상과의 충돌과 퇴적물질 입자간의 충돌에 의하여 발생한다. 하천 퇴적물질의 물리적 강도는 마식에 대한 저항의 정도를 나타내는 것으로 정의할 수 있으나, 이에 대한 실증적인 연구는 큰 진전을 보이지 못해왔다. 본 연구에서는 퇴적물질의 마식에 영향을 미치는 요소들(퇴적물질의 물리적강도, 퇴적물질의 크기, 퇴적물질의 양등)의 관계를 파악하기 위해서 마식기를 이용한 물리적 실험을 실시하였으며, 특히 퇴적물질의 물리적 강도가 마식율에 미치는 영향을 분석하는데 강조점을 두고 있다. 이 실험에서는 266개의 퇴적물을 이용했으며, 퇴적물질의 양과 퇴적물질의 평균 무게에 따라 11개의 소집단으로 나눠 실험하였다. 각 실험은 1시간 단위로 이루어 졌으며 퇴적물질은 최장 8시간 동안 마식되었다. 마식율은 각 실험단계마다 퇴적물질 입자 무게의 변동으로 측정하였으며, 총 2,128번의 측정이 이루어졌다. 퇴적물질의 물리적 강도는 시험이 종료한 뒤에 파괴하중을 측정하여 계산한 점 하중강도지수를 통해 측정하였다. 퇴적물질의 점하중강도지수는 마식율과 음의 상관이 있는 것으로 나타났으나, 두 변수들 간의 회귀식의 설명율($R^2$)은 0.22로 나타났다. 퇴적물질의 전반적인 마식은 실험 초기에는 빠르게 진행되지만, 풍화각이 제거된 뒤에는 마식율이 급감하는 경향을 보여주고 있다. 풍화각을 제거하는 초기 단계에는 퇴적물질의 물리적 강도와 마식율의 관계가 미약하지만 이후로 점점 설명율이 상승한다. 이 실험 결과에 의하면 퇴적물질의 물리적 강도는 마식율의 결정적인 설명변수가 아닐 수 있으며, 물리적 속성 이외에도 퇴적물질의 운반조건 등이 마식율에 큰 영향을 주는 것으로 판단된다.

Keywords

References

  1. 김익재.이병국.최지용.한대호, 2007, 수생태계 보호를 위한 토사관리방안, 한국환경정책.평가연구원
  2. 김재석, 2004, 암반사면의 장기적 안정성평가기법, 영남대학교 박사학위논문
  3. 김종연, 2004, '기반암하상하천에서의 퇴적물 특성변화에 대한 연구,' 한국지형학회지, 11(3), 47-61
  4. 김종연, 2007, '마식에의한 기반암면 표면변화에 대한 실험연구,' 대한지리학회지, 42(4), 506-525
  5. 김해경.고영구.오강호, 2004, '고흥지역에 분포하는 백악기 응회암의 역학적 특성에 관한 연구,' 지질공학, 14, 273-285
  6. 이창섭.조태진.이상배.원경식, 2007, '제주도 한라산 조면암의 풍화특성에 관한 연구,' 지질공학, 17, 235-251
  7. 최성윤, 2005, 붕괴사면의 사례 검토 및 붕괴요인 분석에 관한 연구, 영남대학교 석사학위논문
  8. Adams, J., 1979, Wear of unsound pebbles in River headwaters, Science, 203, 171-172 https://doi.org/10.1126/science.203.4376.171
  9. ASTM, 2003, Standard test method for determination of the point load strength index of rock, ASTM D-5731-02
  10. Bonney, T. G., 1888, Observation on the roundings of pebbles by alpine rivers, with a note on their bearing uponthe origin of the Bunter conglumerate, The geological magazine, New Series, Decade III, 5, 54-61
  11. Bradley, W. C., 1970, Effect of weathering on abrasion of granitic gravel, Colorado river(Texas), Geological Society of America Bulletin, 81, 61-80 https://doi.org/10.1130/0016-7606(1970)81[61:EOWOAO]2.0.CO;2
  12. Brewer, P. A., 1991, Sediment reduction processes in natural rivers, Unpublished Ph.D Dissertation, University of Wales, Aberyswyth
  13. Brewer, P. A., Leeks, G. J. L., and Lewin, J., 1992, Direct measurement of in-channel abrasion processes, in Bogen, J., Welling, D. E., and Day, T. J. (eds.), Erosion and sediment transport monitoring programmes in river basin, IAHS publication no.210, 21-29
  14. British Standard, 1998, Tests for mechanical and physical properties of aggregates part 2: Method for the determination of resistance to fragmentation, BS EN 1097-2:1998
  15. Day, M. J., 1980, Rock hardness: Field assessment and geomorphic importance, Professional Geographer, 32, 72-81 https://doi.org/10.1111/j.0033-0124.1980.00072.x
  16. Heller, P. L., Beland, P. E., Humphrey, N. F., Konrad, S. K., Lynds, R. M., McMillan, M. E., Valetine, K. E., Widman, Y. A., and Furbish, D. J., 2001, Paradox of downstream fining and weathering-rind formation in the lower Iowa Hoh river, Olympic Peninsula, Washington, Geology, 29, 971-974 https://doi.org/10.1130/0091-7613(2001)029<0971:PODFAW>2.0.CO;2
  17. Jones, L. S. and Humphrey, N. F., 1997, Weathering-controlled abrasion in a coarse-grained, meandering reach of the Rio Grande: Implications for the rock record, Geological Society of America Bulletin, 109, 1080-1088 https://doi.org/10.1130/0016-7606(1997)109<1080:WCAIAC>2.3.CO;2
  18. Kim, J. Y., 2004, Controls over bedrock channel incision, unpublished Ph.D dissertation, University of Glasgow
  19. Kodama, Y., 1992, Effect of abrasion on downstream gravel size relation in the Watarase river, Japan, Environmental Research Center Papers 15, Environmental Research Center, The University of Tsukuba
  20. Krumbein, W. C., 1941, The effect of abrasion on the size, shape and roundness of the rock fragments, Journal of Geology, 49, 482-520 https://doi.org/10.1086/624985
  21. Kuenen, Ph. H., 1959, Experimental abrasion:3 Fluviatile action on sand, American Journal of Science, 257, 172-190 https://doi.org/10.2475/ajs.257.3.172
  22. Lee, H. -Y., You, J. -Y., and Lin, Y. -T., 2002, Continuous saltating processes of multiple sediment particles, Journal of Hydraulic Engineering, 128, 443-450 https://doi.org/10.1061/(ASCE)0733-9429(2002)128:4(443)
  23. Lewin, J. and Brewer, P. A., 2002, Laboratory simulation of clast abrasion, Earth Surfaces Processes and Landforms, 27, 145-164 https://doi.org/10.1002/esp.306
  24. Loveday, B. K. and Naidoo, D., 1997, Rock abrasion in autogenous milling, Minerals Engineering, 10, 603-612 https://doi.org/10.1016/S0892-6875(97)00039-3
  25. Marshall, P., 1928, The wearing of beach gravels, Transactions and Proceedings of the New Zealand Institute, 58, 507-532
  26. Marshall, P., 1930, Beach gravels and sands, Transactions and Proceedings of the New Zealand Institute, 60, 324-365
  27. Mikos, M., 1994, The downstream fining of gravel-bed sediments in the alpine Rhine river, in Eigenzinger, P., and Schmidt, K. -H.(eds.), Dynamics and Geomorphology of Mountain River, Springer Verlag, Berlin, 93-108
  28. Mikos, M. and Jaeggi, M. N. R., 1995, Experiments on motion of sediment mixtures in a tumbling mill to study fluvial abrasion, Journal of Hydraulic Research, 33, 751-772 https://doi.org/10.1080/00221689509498550
  29. Sarmiento, A., 1945, Experimental study of pebble abrasion, Unpublished M.Sc Dissertation, The University of Chicago
  30. Schbert, C., 1964, Size-frequency distributions of sandsized grains in an abrasion mill, Sedimentology, 3, 288-295 https://doi.org/10.1111/j.1365-3091.1964.tb00643.x
  31. Schumm, S. A. and Stevens, M. A., 1973, Abrasion in place: A mechanism for rounding and size reduction of coarse sediments in rivers, Geology, 1, 37-40 https://doi.org/10.1130/0091-7613(1973)1<37:AIPAMF>2.0.CO;2
  32. Sklar, L. S. and Dietrich, W. E., 2001, Sediment and rock strength controls on river incision into bedrock, Geology, 29, 1087-1090 https://doi.org/10.1130/0091-7613(2001)029<1087:SARSCO>2.0.CO;2
  33. Thompson, D. and Wohl, E. E., 1998, Flume experimentation and simulation of bedrock channel processes, in Tinkler, K. J. and Wohl, E. E. (eds.), Rivers over rock: Fluvial processes in bedrock channels, American Geophysical Union, Washington
  34. Wentworth, C. K., 1919, A laboratory and field study of cobble abrasion, Journal of Geology, 28, 507-521
  35. Whipple, K. X., Anderson, R. S., and Hancock, G. S., 2000, River incision into bedrock: Mechanics and relative efficacy of plucking, abrasion, and cavitation, Geological Society of America Bulletin, 112, 490-503 https://doi.org/10.1130/0016-7606(2000)112<0490:RIIBMA>2.3.CO;2
  36. Wolman, M. G., 1954, A method of sampling coarse river-bed material, EOS, Transactions American Geophysical Union, 35, 951-956 https://doi.org/10.1029/TR035i006p00951