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

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

DOI QR Code

Experimental Study on Influence of Ground Collapse due to Ground Water Level Lowering

지하수위 저하가 지반함몰에 미치는 영향에 관한 실험적 연구

  • Kim, Sukja (Department of Civil Engineering, College of Engineering, Chungnam National University) ;
  • Jung, Kwansue (Department of Civil Engineering, College of Engineering, Chungnam National University)
  • Received : 2018.10.05
  • Accepted : 2018.10.25
  • Published : 2018.11.01
Download PDF
⟨ Previous Next ⟩

Abstract

According to recent ground collapse occurrence, ground subsidence is increasing every year in downtown area, which is a social problem. The purpose of this study is to investigate the relationship between ground water level lowering and ground collapse through laboratory model experiments. After mixing 1:1 granite weathered soil with sand, sandy soil was formed as a relative density of 30%, 50%, and 80%. And then the changes of soil discharge with change of groundwater level were compared. The physical property of material of which particle distribution were well graded with maximu dry unit weight of $1.94kg/cm^3$ and internal friction angle of 37degrees. Ground water levels were measured at 10 cm, 20 cm, and 30 cm from the bottom. As a result, the experiment shows that the higher the groundwater level works the higher the discharge velocity and the magnitude of underground cavity also increases with elapsed time. Finally, the cumulative quantity of soil discharge occurred up to 30 kg at the elapsed time, 35 minutes. It was also confirmed that the range of ground collapse increased due to soil discharge with ground water level lowering.

최근 지반사고 발생통계에 따르면 도심지를 중심으로 지반함몰 및 침하발생 빈도수가 매년 증가하고 있어 사회적으로 문제가 되고 있다. 이 연구는 지반공동현상 실내모형실험을 통해 지하수위 변동과 지반함몰과의 연관성을 규명하고자 하였다. 화강풍화토와 표준사를 1:1로 혼합한 후 상대다짐도 30%, 50%, 80%로 사질지반을 조성하고, 지하수위 변화에 따른 토사유출량의 변화를 비교분석하였다. 사용재료의 물리적 특성은 입도분포가 양호한 모래질로서 최대건조단위중량 $1.94kg/cm^3$, 내부마찰각 $37^{\circ}$로 조성하였다. 하단으로부터 10cm, 20cm, 30cm 높이에 지하수위를 조성한 후 유출량을 분석하였다. 실험결과 지하수위가 높을수록 유출속도가 증가하며, 시간에 따른 공동의 크기도 증가하는 것으로 나타났다. 시간에 따른 토사의 누적유출량은 35분 경과 후 최대 30kg까지 발생하였으며, 지하수 하강에 따른 토사유출로 인해 지반함몰 범위가 증가한 것을 확인하였다.

Keywords

References

  1. 국토교통부 (2015), 지반침하(함몰) 안전관리 매뉴얼.
  2. 국토교통위원회 (2015), 지하안전관리에 관한 특별법 검토 보고서.
  3. 서울시청 (2013), 석촌호수 수위저하원인 자문의견서.
  4. Chung, J. S., Lee, S. G., Lee, G. Y., Jung, H. W. and Kim, H. J. (2015), A Case study on the effects on underground structure due to changes in the groundwater level and ground Stress, Journal of the Korean Geo-Environmental Society, Vol. 16, No. 9, pp. 13-21 (In Korean). https://doi.org/10.14481/jkges.2015.16.9.13
  5. Das, B. M. and Sobhan, K. (2013), Principle of Geotechnical Engineering, Cengage Learning, USA, p. 171.
  6. Jeong, H. J. (2018), Analysis of ground subsidence characteristics by influence factor through laboratory model test, Ph. D. thesis, Chonnam National University (In Korean).
  7. Jeong, H. S. (2018), Detection of cavities under pavements using 2D full seismic waveform inversion method, Ph. D. thesis, Incheon National University (In Korean).
  8. Jeong, S. Y., Karoui T., Jeong, Y. H. and Kim D. S. (2017), Experimental study on ground subsidence and underground cavity expansion under various conditions, Journal of Engineering Geology, Vol. 27, No. 2, pp. 143-152 (In Korean). https://doi.org/10.9720/KSEG.2017.2.143
  9. Joung, H. Y. and Lee, G. H. (2017), A study on risk influence factors of ground subsidence through soil investigation analysis, Journal of Korean Society of Disaster & Security, Vol. 10, No. 1, pp. 43-46 (In Korean). https://doi.org/10.21729/KSDS.2017.10.1.43
  10. Kim, S. W., Jeong, S. W., Yeom, B. W., Ryu, D. W., Lee, H. J., Jeong, B. J., Bang, E. S. and Lee, I. H. (2016), Results of ground subsidence simulation according to the degree of compaction of sand, Proceedings of KSEG 2016 Spring Conference, pp. 85-86 (In Korean).
  11. Kim, Y. H., Kim, J. B., Kim, D. W. and Han, J. G. (2017), Experimental study on generating mechanism of the ground subsidence of due to damaged waters supply pipe, Journal of Korean Geosynthetics Society, Vol. 16, No. 2, pp. 139-148 (In Korean). https://doi.org/10.12814/jkgss.2017.16.2.139
  12. KS F 2302 (2017), Standard test method for particle size distribution of soils, Korea Standard Association.
  13. KS F 2312 (2016), Standard test method for soil compaction using a rammer, Korea Standard Association.
  14. KS F 2343 (2017), Standard test method for direct shear test of soils under consolidation drained conditions, Korea Standard Association.
  15. Lee, K. Y. and Kang, S. J. (2014), Sinkhole swallowing a town - Cause and countermeasure, Gyeonggi Research Institute (In Korean).
  16. Park, J. Y., Jang, E. G., Kim, H. J. and Ihm, M. H. (2017), Classification of ground subsidence factors for prediction of ground subsidence risk (GSR), Journal of Engineering Geology, Vol. 27, No. 2, pp. 153-164 (In Korean). https://doi.org/10.9720/KSEG.2017.2.153
  17. Shin, E. C., Kang, J. K., Shin, H. S. and Yoo, J. S. (2017), Stability analysis of underground express highway tunnel in Incheon, Proceedings of 19th International Conference on Soil Mechanics and Geotechnical Engineering, Seoul, pp. 1773-1776.