All Issue

2024 Vol.20, Issue 2 Preview Page

Original Article

Evaluating the Influence of Post-Earthquake Rainfall on Landslide Susceptibility through Soil Physical Properties Changes

지진이후 강우의 산사태 발생 영향성 평가를 위한 토양물성값 변화 분석

서준표1ㆍ유송2ㆍ이기환3ㆍ이기하4ㆍ오세욱5*

Junpyo Seo1, Song Eu2, KiHwan Lee3, Giha Lee4, Sewook Oh5*

1Researcher official, Division of Landslide Division, National Institute of Forest Science, Seoul, Republic of Korea
2Researcher official, Division of Landslide Division, National Institute of Forest Science, Seoul, Republic of Korea
3Researcher official, Division of Landslide Division, National Institute of Forest Science, Seoul, Republic of Korea
4Professor, Department of Construction & Disaster Prevention Engineering, Kyungpook National University, Sangju, Republic of Korea
5Professor, Department of Construction & Disaster Prevention Engineering, Kyungpook National University, Sangju, Republic of Korea
30 June 2024. pp. 270-283
PDF Citation
Abstract
Purpose: Considering the rising frequency of earthquakes in Korea, it is crucial to revise the rainfall thresholds for landslide triggering following earthquake events. This study was conducted to provide scientific justification and preliminary data for adjusting rainfall thresholds for landslide early warnings after earthquakes through soil physical experiments. Method: The study analyzed the change in soil shear strength by direct shear tests on disturbed and undisturbed samples collected from cut slopes. Also, The study analyzed the soil strength parameters of remolded soil samples subjected to drying and wetting conditions, focusing on the relationship between the degree of saturation after submergence and the strength parameters. Result: Compaction water content variation in direct shear tests showed that higher water content and saturation in disturbed samples led to a significant decrease in cohesion (over 50%) and a reduction in shear resistance angle (1~2°). Additionally, during the ring shear tests, the shear strength was observed to gradually decrease once water was supplied to the shear plane. The maximum shear strength decreased by approximately 65-75%, while the residual shear strength decreased by approximately 53-60%. Conclusion: Seismic activity amplifies landslide risk during subsequent rainfall, necessitating proactive mitigation strategies in earthquake-prone areas. This research is anticipated to provide scientific justification and preliminary data for reducing the rainfall threshold for landslide initiation in earthquake-susceptible regions.
Keywords
Earthquake-induced Landslide
Direct Shear Test
Ring Shear Test
Soil Cohesion
Soil Physical Properties
연구목적: 국내에서 지속적으로 지진이 발생하고 있기 때문에 지진 발생 후에 대한 산사태 유발 임계강우량의 하향 조정이 요구되고 있다. 본 연구에서는 토양의 물리적 실험을 통해 지진 발생 이후 산사태 예·경보를 위한 임계강우량 조정의 과학적 근거 확보 및 기초자료를 제공할 목적으로 수행되었다. 연구방법: 절토 사면에서 채취한 교란 및 비교란 시료를 대상으로 직접전단시험을 통한 토양의 전단강도 변화를 분석하고, 건조 및 습윤 조건으로 재성형된 시료의 수침후 포화도에 따른 토양의 강도정수를 분석하였다. 연구결과: 다짐함수비를 변화시키며 직접전단시험을 수행한 결과 교란시료 함수비 및 포화도가 증가할수록 점착력은 50% 이상 감소하였고, 전단저항각은 1~2° 감소하였다. 또한, 링전단시험 중 물을 공급한 결과 전단면에 물이 침투되는 순간부터 전단강도의 값이 서서히 감소되는 것으로 나타났으며, 최대전단강도는 약 65~75%, 잔류전단강도는 약 53~60% 감소하였다. 결론: 지진과 이후 강우가 발생하였을 때는 사면붕괴 가능성이 증가하므로 이에 대한 대책이 필요하며, 본 연구의 결과는 지진이 발생한 지역에서 산사태를 유발하는 강우임계값을 하향해야 하는 과학적 근거 및 기초자료로 활용될 수 있을 것으로 기대된다.
키워드
지진유발 산사태
직접전단시험
링전단시험
토양점착력
토양물리적 특성
References
  1. Chae, B.-G., Choi, J.-H, Jeong, H.-K. (2016). "A feasibility study of a rainfall triggering index model to warn landslides in Korea." The Journal of Engineering Geology, Vol. 26, No. 2, pp. 325-250. 10.9720/kseg.2016.2.235
  2. Guo, D., Hamada, M. (2013). "Qualitative and quantitative analysis on landslide influential factors during Wenchuan earthquake: A case study in Wenchuan county." Engineering Geology, Vol. 152, pp. 202-209. 10.1016/j.enggeo.2012.10.012
  3. Harp, E.L., Keefer, D.K., Sato, H.P., Yagi, H. (2011). "Landslide inventories: The essential part of seismic landslide hazard analyses." Engineering Geology, Vol. 122, pp. 9-21. 10.1016/j.enggeo.2010.06.013
  4. Hiramatsu, S., Yoshioka, M. (2004). "Experimental study on effect of impact force caused by earthquake on slope stability." Journal of Japan Society of Erosion Control Engineering, Vol. 56, No. 5, pp. 61-66.
  5. Hong, Y., Adler, R.F. (2007). "Towards an early-warning system for global landslides triggered by rainfall and earthquake." International Journal of Remote Sensing, Vol. 28, pp. 3713-3719. 10.1080/01431160701311242
  6. Hotta, N., Kan, Y., Shuin, Y., Wei, T., Zhang, Z., Chen, H., Suzuki, M. (2005). "Relationship between slope failures and precipitation before and after the Chi-Chi earthquake investigated using long-term repair records of forestry roads in the National Taiwan University Forest." Japan Society Erosion Control Engineering, Vol. 58, No. 1, pp. 3-13.
  7. Huang, R., Pei, X., Fan, X., Zhang, W., Li, S., Li, B. (2012). "The characteristics and failure mechanism of the largest landslide triggered by the Wenchuan earthquake, May 12, 2008, China." Landslides, Vol. 9, pp. 131-142. 10.1007/s10346-011-0276-6
  8. Jeon, S.-K., Kim, D.-M., Choi, W.-I., Choi, E.-H. (2014). "Prediction of the landslide and effect on heritage located in mountain induced earthquake." The Journal of Korean Society of Hazard Mitigation, Vol. 14, No. 2, pp. 139-148. 10.9798/KOSHAM.2014.14.2.139
  9. Jeong, S.-W., Fukuoka, H., Song, Y.-S. (2013). "Ring-shear apparatus for estimating the mobility of debris flow and its applicaton." Journal of the Korean Society of Civil Engineers, Vol. 33, No. 1, pp. 181-194. 10.12652/Ksce.2013.33.1.181
  10. Kang, M.-J., Kim, K.-D., Seo, J.-P., Woo, C.-S., Lee, C.-W. (2020). "Analysis of the occurrence characteristics of earthquake-induced landslide through a media report: Focus on international cases reported in domestic media during the 10 years (2009-2018)." Journal of the Korea Society of Disaster Information, Vol. 16, No. 3, pp. 440-448.
  11. KIGAM (2023). 2023 East Sea (Gangwon) Consecutive Earthquake Report. Daejeon, Korea.
  12. Lee, C.T. (2014). "Statistical seismic landslide hazard analysis: An example from Taiwan." Engineering Geology, Vol. 182, pp. 201-212. 10.1016/j.enggeo.2014.07.023
  13. Lee, C.T., Huang, C.C., Lee, J.F., Pan, K.L., Lin, M.L., Dong, J.J. (2008). "Statistical approach to earthquake-induced landslide susceptibility." Engineering Geology, Vol. 100, pp. 43-58. 10.1016/j.enggeo.2008.03.004
  14. Lee, C.-W., Kim, D.-Y., Woo, C.-S., Kim, Y.-S., Seo, J.-P., Kwon, H.-J. (2015). "Construction and operation of the national landslide forecast system using soil water index in Republic of Korea." The Journal of Korean Society of Hazard Mitigation, Vol. 15, No. 6, pp. 213-221. 10.9798/KOSHAM.2015.15.6.213
  15. Lee, J.-Y., Han, J.-T., Baek, Y., Park, D.-H., Lee, J.-H., Park, I.-J. (2014). "Development of prediction method onsidering geometrical amplification characteristics of slope 2: Construction of landslide hazard map during arthquakes in Seoul." The Journal of Korean Society of Hazard Mitigation, Vol. 14, No. 5, pp. 85-92. 10.9798/KOSHAM.2014.14.5.85
  16. Lee, S.-I., Seo, J.-I., Kim, J.-H., Ryu, D.-S., Seo, J.-P., Kim, D.-Y., Lee, C.-W. (2017). "International research trend on mountainous sediment-related disasters induced by earthquakes." Journal of Korean Forest Society, Vol. 106, No. 4, pp. 431-440.
  17. Lin, C.W., Shieh, C.L., Yuan, B.D., Shieh, Y.C., Liu, S.H., Lee, S.Y. (2003). "Impact of Chi-Chi earthquake on the occurrence of landslides and debris flows: Example from the Chenyuan river watershed, Nantou, Taiwan." Engineering Geology, Vol. 71, pp. 49-61. 10.1016/S0013-7952(03)00125-X
  18. Ma, C., Wang, Y., Hu, K., Du, C., Yang, W. (2017). "Rainfall intensity-duration threshold and erosion competence of debris flows in four areas affected by the 2008 Wenchuan earthquake." Geomorphology, Vol. 282, pp. 85-95. 10.1016/j.geomorph.2017.01.012
  19. Newmark, N.M. (1965). "Effects of earthquakes on dams and embankments." Geotechnique, Vol. 15, No. 2, pp. 139-160. 10.1680/geot.1965.15.2.139
  20. Nomura, Y., Okamoto, A., Kuramoto, K., Ikeda, H. (2014). "Landslide-triggering rainfall thresholds after major earthquakes for early warning." International Journal of Erosion Control Engineering, Vol. 7, No. 2, pp. 56-62. 10.13101/ijece.7.56
  21. Ou, G.Q., Pan, H.L., Liu, J.F., Fan, J.R., You, Y. (2010). "Characteristics of sediment-related disasters triggered by the Wenchuan earthquake." International Journal of Erosion Control Engineering, Vol. 3, No. 1, pp. 59-68. 10.13101/ijece.3.59
  22. Park, J.-H., Soe, J.-I., Ma, H.-S., Kim, D.-Y., Kang, M.-J., Kim, K.-D. (2019). "Topography and soil characteristics related to land creep in 37 areas in South Korea." Journal of Korean Society of Forest Science, Vol. 108, No. 4, pp. 540-551.
  23. Park, S.-S., Jeong, S-W., Yoon, J.-H., Chae, B.-G. (2013). "Ring shear characteristics of two different soils." Journal of the Korean Geotechnical Society, Vol. 29, No. 5, pp. 39-52. 10.7843/kgs.2013.29.5.39
  24. Seo, J.-I., Lee, S.-I., Kweon, H.-K., Chun, K.-W., Kim, S.-W., Jun, K.-W., Kim, J.-H., Lee, C.-W. (2018). "Future research direction in response to mountainous sediment-related disasters induced by earthquakes in South Korea." Crisisonomy, Vol. 14, No. 3, pp. 119-138. 10.14251/crisisonomy.2018.14.3.119
  25. Seo, J.-P., Eu, S., Lee, K.-H., Lee, C.-W., Woo, C.-S. (2021). "A study on risk assessment method for earthquake-induced landslides." Journal of the Korea Society of Disaster Information, Vol. 17, No. 4, pp. 694-709.
  26. Shuin, Y., Hotta, N., Suzuki, M., Osanai, N., Okamoto, A. (2012). "Preliminary study on landslide-triggering rainfall thresholds after an earthquake." Journal of Japan Society of Erosion Control Engineering, Vol. 65, No. 2, pp. 16-22.
  27. Tang, C., Liang, J.T. (2008). "Characteristics of debris flows in Beichuan epicenter of the Wenchuan earthquake triggered by rainstorm on September 24, 2008." Journal of Engineering Geology, Vol. 16, pp. 49-61.
  28. Tomita, Y., Sakurai, W., Naka, N. (1996). "Study on the extension of collapse by rainfall after earthquakes in the Rokko mountain range." Journal of Japan Society of Erosion Control Engineering, Vol. 48, No. 6, pp. 15-21.
  29. Torii, N., Okimura, T., Katou, S. (2007). "Experimental study on slope failure mechanism induced by rainfall after earthquake." Journal of Japan Society of Erosion Control Engineering, Vol. 63, No. 1, pp. 140-149. 10.2208/jscejc.63.140
Information
  • Publisher :The Korean Society of Disaster Information
  • Publisher(Ko) :한국재난정보학회
  • Journal Title :Journal of the Society of Disaster Information
  • Journal Title(Ko) :한국재난정보학회논문집
  • Volume : 20
  • No :2
  • Pages :270-283
  • DOI :https://doi.org/10.15683/kosdi.2024.6.30.270
Journal Informaiton Journal of the Society of Disaster Information Journal of the Society of Disaster Information
  • NRF
  • KISTI Current Status
  • KISTI Cited-by
  • crosscheck
  • orcid
  • open access
  • ccl
Journal Informaiton Journal Informaiton - close