DOI QR코드

DOI QR Code

A Study on Efficient Design of Rockfall Prevention Netting

낙석방지망의 효율적 설계를 위한 기초연구

  • Lee, Jundae (Department of Civil Engineering, Semyung University) ;
  • Park, Soobeom (Department of Civil Engineering, Chungbuk National University) ;
  • Bae, Wooseok (NANO-GEO ENC Co., Ltd.)
  • Received : 2014.08.19
  • Accepted : 2014.10.02
  • Published : 2014.12.01

Abstract

In order to obtain basic data for reasonable design of rockfall prevention net unreasonably being designed according to experiences, this paper determined a standard cross section and analyzed the effects of parameters such as inclination and height of slope faces, rockfall weight, separation distance on rockfall behaviors such as bounce height, kinetic energy and passage rate. The weight of rockfall changed from 400 kg to 700 kg and then to 1,000 kg. With the height of 20 m as the standard, the test was conducted with the inclination at $63^{\circ}$ and $55^{\circ}$ which may affect rockfall behaviors. Analysis was made while changing the fall height of rockfall from 3 m to 15 m and then to 20 m, thereby analyzing and evaluating changes in maximal kinetic energy occurring in the base of slope. According to the analysis result, in designing a rockfall prevention wire net, a design considering various conditions including inclination of the slope, expected size or weight of rockfall, situation of the slope and the shape of rockfall, and rockfall trace is judged necessary beyond the current uniform application.

본 논문에서는 경험에 따라 비합리적으로 설계되고 있는 낙석방지망의 합리적인 설계를 위한 기초자료를 획득하기 위해 표준 단면을 결정하고 비탈면의 경사, 높이, 낙석의 무게, 이격거리 등의 매개변수가 도약높이나 운동에너지, 통과속도 등 낙석의 거동에 미치는 영향을 분석하였다. 낙석의 무게는 400, 700, 1,000 kg으로 변화하고 20 m 높이를 기준으로 낙석방호시설이 낙석의 거동에 영향을 미칠 수 있는 1:0.5($63^{\circ}$), 1:0.7($55^{\circ}$)의 경사에 대해 수행하였으며, 낙석의 낙하높이를 3, 15, 20 m를 변경시켜가면서 해석을 실시하여 사면 하부에 발생하는 최대운동에너지의 변화를 분석 평가하였다. 해석결과, 낙석방지망의 설계 시 현행과 같이 일률적인 적용에서 벗어나 사면의 경사와 예상되는 낙석의 규모나 무게, 법면의 상황 및 낙석의 모양, 낙석 운동형태 등 다양한 조건을 고려한 설계가 필요할 것으로 판단된다.

Keywords

References

  1. 국토해양부 (2009a), 건설공사 비탈면 설계기준, pp. 371-398.
  2. 국토해양부 (2009b), 도로 안전 시설 설치 및 관리지침 제4편 낙석방지시설, pp. 447-515.
  3. 高速道路調査會 (1974), 落石防護施設の設置に関する調査研究報告書, 財)高速道路調査會, 東京, p. 37.
  4. Azzoni, A., La Barbera, G. and Zaninetti, A. (1995), Analysis and prediction of rockfalls using a mathematical model, International Journal Rock Mechanics and Mining Sciences & Geomechanics Abstracts, Vol. 32, No. 7, pp. 709-724. https://doi.org/10.1016/0148-9062(95)00018-C
  5. Bozzolo, D. and Pamini, R. (1986), Simulation of rock falls down a valley side, Acta Mechanica 63, pp. 113-130. https://doi.org/10.1007/BF01182543
  6. Brawner, C. O. (1994), Rockfall hazard mitigation methods participant workbook, National Highway Institute Course No.13219, FHWA SA-93-085, U.S. Department of Transportation, Federal Highway Institution, Washington, DC., pp. 1-25.
  7. Broili, L. (1973), In situ tests for the study of rockfall, Geologia Applicatae Idrogeologia, Vol. 8, No. 1, pp. 105-111.
  8. Budetta, P. and Panico, M. (2002), Il metodo rockfall hazard rating system, Modificato per la valutazione del rischio da caduta massi, Geologia Tecnica ed Ambientale, 2, pp. 3-13 (in Italy).
  9. Evans, S. G. and Hungr, O. (1993), The assessment of rockfall hazard at the base of talus slopes, Canadian Geotechnical Journal, Vol. 30, No. 4, pp. 620-636. https://doi.org/10.1139/t93-054
  10. Hoek, E. (1998), Rock engineering, Evert Hoek Consulting Engineer Inc., pp. 115-136.
  11. Hwang, Y. C., Kim, S. H. and Lee, S. H. (2010), Proposal for installation of rockfall protection fence considering rockfall trace, Proceedings of Korean Geo-Enviromental Society, Vol. 2010, pp. 351-357 (in Korean).
  12. Jeong, N. S. (2000), Analysis of rockfall movement by initial motion modes, Yonsei University, Master's Thesis, pp. 1-81 (in Korean).
  13. Kim, D. H., Ryu, D. W., Kim, S. C., Yoon, S. K. and Lee, W. J. (2007), Estimation of weight distribution of rockfall block by joint measurement and study on its application to rockfall simulation, Journal of the Korean Geotechnical Society, Vol. 23, No. 11, pp. 67-76 (in Korean).
  14. Kim, K. S. (2010), Contemplation of rockfall simulation parameters and design of rockfall fence, Journal of Korean Geo-Enviromental Society, Vol. 13, No. 1, pp. 344-350 (in Korean).
  15. Labiouse, V. and Heidenreich, B. (2009), Half-scale experimental study of rockfall impacts on sandy slopes, Natural Hazards and Earth System Sciences NHESS, Vol. 9, pp. 1981-1993. https://doi.org/10.5194/nhess-9-1981-2009
  16. Pfeiffer, T. J. and Bowen, T. (1989), Computer simulation of rockfalls, Bull. of the Assoc. of Engineering Geologists, Vol. 26, No. 1, pp. 135-146.
  17. Pierson, L. A., Davis, S. A. and Van Vickle, R. (1990), Rockfall hazard rating system implementation manual, Federal Highway Administration Report FHWA-OR-EG-90-01, FHWA, U.S. Department of Transportation, pp. 1-172.
  18. Ritchie, A. M. (1963), The evaluation of rockfall and its control, Highway Research Board, Vol. 17, pp. 13-28 (in Italy).
  19. Rochet, L. (1987), Application des modeles numeriques de propagation a l'etude des eboulements rocheux, Bulletin Liaison Pont Chaussee 150/151, pp. 84-95 (in French).
  20. Spang, R. M. and Soner, T. H. (1995), Optimized rockfall protection by 'ROCKFALL', 8th International Congress on Rock Mechanics, International Society for Rock Mechanics, Tokyo, Japan, Vol. 3, pp. 1233-1242.
  21. Wu, S. S. (1985), Rockfall evaluation by computer simulation, Transportation Research Record 1031, pp. 1-5.