Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
권호 표지
DOI QR코드

DOI QR Code

Experimental Assessment and Specimen Height Effect in Frost Heave Testing Apparatus

동상시험장비의 실험적 검증 및 시료크기의 영향에 관한 연구

  • Jin, Hyunwoo (Department of Smart City & Construction Engineering, Korea University of Science & Technology) ;
  • Ryu, Byunghyun (Future Technology and Convergence Research, Korea Institute of Civil Engineering and Building Technology) ;
  • Lee, Jangguen (Future Technology and Convergence Research, Korea Institute of Civil Engineering and Building Technology)
  • Received : 2018.11.11
  • Accepted : 2018.12.27
  • Published : 2019.01.01
Download PDF
⟨ Previous Next ⟩

Abstract

Frost heave is one of the representative engineering characteristics in cold regions. In South Korea, which is located in seasonal frost area, structural damage caused by frost heave and thaw happens and the need for research on the frost heave is increasing. In this paper, newly developed transparent temperature-controllable cell is used to focus on the frost heave. Frost susceptible artificial soil is used to analyze water intake rate which is one of the important factors in frost susceptibility criteria. Frost heave rate and water intake rate have similar behavior after heave by freezing of pore water converges. O-ring installed in the upper pedestal to measure water intake rate generates side friction between the inner wall of the freezing cell and O-ring, thereby hindering frost heave. Therefore, the frost susceptibility criteria using the water intake rate is not reliable. It is appropriate to use frost heave rate which has similar behavior with water intake rate. Frost heave tests were performed under two different specimen heights. Overburden pressure, temperature gradient and dry unit weight were set under similar state. Based on laboratory testing results, frost heave is independent on the specimen height.

동상은 동토지역에서 발생하는 대표적인 공학적 특성이다. 계절동토(seasonal frost area)에 해당하는 우리나라는 동결융해에 의한 구조적 피해가 발생하고 동상에 관한 연구의 필요성이 증대되고 있는 실정이다. 본 논문에서는 새롭게 개발한 투명 온도제어형 셀을 활용하여 동상에 관한 연구를 수행하였다. 동상에 민감한 흙을 인공적으로 조성하여 동상민감성 판정에 있어 중요한 인자 중 하나인 물 주입속도(water intake rate)에 관한 분석을 실시하였다. 간극수 동결에 의한 부피팽창(heave by pore water)이 수렴하는 시점 이후에 동상속도(frost heave rate)와 물 주입속도는 거의 유사하게 나타났다. 그러나 물 주입속도를 측정하기 위해 상부 페더스탈에 설치한 O-ring은 몰드 내벽과의 마찰을 발생시켜 동상발생을 저하시켰다. 따라서 물 주입속도를 활용한 동상민감성 판정 기준은 신뢰하기 힘들다고 판단되었으며, 유사한 거동을 보이는 동상속도를 활용하는 것이 적절하다는 결론을 내렸다. 또한, 동상민감성 흙을 활용해 시료크기가 동상에 미치는 영향을 파악하고자 하였다. 시료크기가 다른 2가지 경우에 대해 동상시험을 수행하였으며 상재하중, 온도구배, 그리고 건조단위중량을 동일하게 설정하였다. 실험결과를 토대로 시료크기는 동상에 영향을 미치지 않는다는 것을 발견하였다.

Keywords

HJHGC7_2019_v20n1_67_f0001.png 이미지

Fig. 1. Testing apparatus including the transparent temperature-controllable cell (Jin et al., 2019)

HJHGC7_2019_v20n1_67_f0002.png 이미지

Fig. 2. Grain size distribution curve of artificial soil

HJHGC7_2019_v20n1_67_f0003.png 이미지

Fig. 3. Laboratory frost heave testing results including water intake (Jin et al., 2019)

HJHGC7_2019_v20n1_67_f0004.png 이미지

Fig. 4. Temperature profile of the tested artificial soil

HJHGC7_2019_v20n1_67_f0005.png 이미지

Fig. 5. Decision process for thermal equilibrium and heave rate

HJHGC7_2019_v20n1_67_f0006.png 이미지

Fig. 6. Measurement of side friction without soil

HJHGC7_2019_v20n1_67_f0007.png 이미지

Fig. 7. Frost heave testing results with and without O-ring

HJHGC7_2019_v20n1_67_f0008.png 이미지

Fig. 8. Grain size distribution curve of Halden silt

HJHGC7_2019_v20n1_67_f0009.png 이미지

Fig. 9. Frost heave testing results with different specimen heights

Table 1. Characteristics and freezing method using the transparent temperature-controllable cell

HJHGC7_2019_v20n1_67_t0001.png 이미지

Table 2. Engineering properties of Joomunjin standard sand

HJHGC7_2019_v20n1_67_t0002.png 이미지

Table 3. Boundary conditions for frost heave test (Jin et al., 2019)

HJHGC7_2019_v20n1_67_t0003.png 이미지

Table 4. Calculated and measured heave by pore water (Jin et al., 2019)

HJHGC7_2019_v20n1_67_t0004.png 이미지

Table 5. Boundary conditions for frost heave test without O-ring

HJHGC7_2019_v20n1_67_t0005.png 이미지

Table 6. Engineering properties of Halden soil

HJHGC7_2019_v20n1_67_t0006.png 이미지

Table 7. Boundary conditions for frost heave test of Halden silt

HJHGC7_2019_v20n1_67_t0007.png 이미지

Table 8. Frost heave ratio (ξ)

HJHGC7_2019_v20n1_67_t0008.png 이미지

References

  1. ASTM D5918 (2013), Standard Test Methods for Frost Heave and Thaw Weakening Susceptibility of Soils, American Society for Testing Materials International, West Conshohocken, pp. 1-13.
  2. Beskow, G. (1947), Soil freezing and frost heaving with special application to roads and rail roads, Technological Institute, Northwestern Univ, pp. 1-145.
  3. Croney, D. and Jacobs, J. C. (1967), The frost susceptibility of soils and road materials, No. LR 90, Road Research Laboratory, Crowthorne, pp. 1-68.
  4. GOST 28622 (2012), Standard test methods for frost heave susceptibility of soils, Standard Inform, Moscow, pp. 1-12.
  5. JGS 0172 (2003), Test Method for Frost Susceptibility of Soils, Japan Geotechnical Society, Tokyo, pp. 1-6.
  6. Jin, H. W., Ryu, B. H. and Lee J. (2017), Evaluation on the reliability of frost susceptibility criteria, Journal of the Korean Geo-Environmental Society, Vol. 18, No. 12, pp. 37-45. https://doi.org/10.14481/jkges.2017.18.1.37
  7. Jin, H. W., Ryu, B. H. and Lee J. (2019), Simple frost heave testing method using a temperature-controllable cell, Cold Regions Science and Technology, Vol. 157, pp. 119-132. https://doi.org/10.1016/j.coldregions.2018.09.011
  8. Jones, R. H. (1980), Frost heave of roads, Quarterly Journal of Engineering Geology and Hydrogeology, Vol. 13, pp. 77-86. https://doi.org/10.1144/GSL.QJEG.1980.013.02.02
  9. Konrad, J. M. (1987), Procedure for determining the segregational potential of freezing soils, Geotechnical Testing Journal, Vol. 10, No. 2, pp. 51-58. https://doi.org/10.1520/GTJ10933J
  10. Konrad, J. M. (1994), Frost heave in soils: concepts and engineering, Canadian Geotechnical Journal, Vol. 31, pp. 223-245. https://doi.org/10.1139/t94-028
  11. Konrad, J. M. and Morgenstern, N. R. (1980), A mechanistic theory of ice lens formation in fine-grained soils, Canadian Geotechnical Journal, Vol. 17, pp. 473-486. https://doi.org/10.1139/t80-056
  12. Konrad, J. M. and Morgenstern, N. R. (1981), The segregation potential of a freezing soil, Canadian Geotechnical Journal, Vol. 18, pp. 482-491. https://doi.org/10.1139/t81-059
  13. Lackner, R., Amon, A. and Lagger, H. (2005), Artificial ground freezing of fully saturated soil, Journal of Engineering Mechanics, Vol. 131, No. 2, pp. 211-220. https://doi.org/10.1061/(ASCE)0733-9399(2005)131:2(211)
  14. Penner, E. and Ueda, T. (1977), The dependence of frost heaving on load application, Proceedings of an International Symposium on Frost Action in Soils, Vol. 1, pp. 92-101.
  15. Ryu, B. H., Jin, H. W. and Lee J. (2016), Experimental study of frost heaveing using temperature controlled triaxial cell, Journal of the Korean Geo-Environmental Society, Vol. 17, No. 6, pp. 22-31.
  16. Taber, S. (1929), Frost heaving, The Journal of Geology, Vol. 37, No. 5, pp. 428-461. https://doi.org/10.1086/623637