Abstract
In Hong Kong, design practice adopts the hydrodynamic load model to estimate the dynamic soil debris impact load on reinforced concrete debris-resisting barriers. A dynamic coefficient of 2.5 is empirically adopted, which takes into account the effect of the impact of boulders up to 0.5 m in diameter. With a view to rationalising the design of reinforced concrete debris-resisting barriers, the Geotechnical Engineering Office (GEO), in collaboration with the Hong Kong University of Science and Technology (HKUST), initiated a study to investigate the dynamic impact of soil debris. In particular, a series of large-scale impact tests using 4 m3 realistic debris mix and a 1.8-m-high reinforced concrete model barrier were conducted in the flume facility in the Kadoorie Centre in Hong Kong. The tests were well controlled, and the flow kinematics, including flow depth and flow speed, and the time history of the impact load at the wall stem subject to the debris impact were measured, which provided critical test data on assessment of the hydrodynamic load of soil debris hitting reinforced concrete structures. The scale of these physical impact tests under such a controlled environment was unique as compared with other studies in the literature. To further examine the dynamic impact force, a calibrated numerical model using a three-dimensional finite-element computer package, namely LS-DYNA, was adopted to simulate the impact scenario for a real-scale debris flow event of 400 m3, where an arbitrary Lagrangian-Eulerian technique was adopted to simulate debris materials. Based on both the experiments and numerical analyses, debris run-up along the wall stem was observed when the debris hit the model barriers. Under the experimental setting, the hydrodynamic soil debris pressure coefficients were consistently found close to unity, which are generally in line with that used in overseas technical guidelines or design practice. This study enhances fundamental understanding of the soil debris impact mechanism on reinforced concrete barriers and provides scientific evidence to rationalise the design guidelines used in Hong Kong.
Similar content being viewed by others
References
Albaba A, Lambert S, Faug T (2018) Dry granular avalanche impact force on a rigid wall: analytic shock solution versus discrete element simulations. Phys Rev E 97:052903-1-12
ASI (2013) ONR 24801 protection works for torrent control—static and dynamic actions on structures. Austrian Standard Institute, Austria
Brighenti R, Segalini A, Ferrero AM (2013) Debris flow hazard mitigation: a simplified analytical model for the design of flexible barriers. Comput Geotech 54:1–15
Bugnion L, McArdell BW, Bartelt P, Wendeler C (2011) Measurements of hillslope debris flow impact pressure on obstacles. Landslides 9:179–187
CAGHP (2018) Specification of design for debris flow prevention (T/CAGHP 021-2018). China Association of Geological Hazard Prevention, 55 p. (in Chinese)
Canelli L, Ferrero AM, Migliazza R, Segalini A (2012) Debris flow risk mitigation by the means of rigid and flexible barriers—experimental tests and impact analysis. Natural Hazard and Earth System Sciences 12:1693–1699. https://doi.org/10.5194/nhess-12-1693-2012
Cheung AKC, Yiu J, Lam HWK, Sze EHY (2018) Advanced numerical analysis of landslide debris mobility and barrier interaction. HKIE Transactions 25(2):76–89
Cui P, Chen XQ, Wang YY, Hu KH, Li Y (2005) Jiang-jia Ravine debris flows in south-western China. In: Jakob M, Hungr O (eds) Debris-flow hazards and related phenomena. Springer, Berlin, pp 565–594
Daido A (1993) Impact force of mud debris flows on structures, Technical Session B. Proceedings of the XXV IAHR Congress. Tokyo, Japan 211–213
Fei XJ, Shu AP (2004) Movement mechanism and disaster control for debris flow. Tsinghua University Press, Beijing (in Chinese), p 216
Huang Y, Yiu J, Pappin J, Sturt R, Kwan JSH, Ho KKS (2014) Numerical investigation of landslide mobility and debris-resistant flexible barrier with LS-DYNA. In Proceedings of the 13th International LS-DYNA Users Conference, Dearborn, 8-10 June 2014. Livermore Software Technology Corporation, Livermore
Hungr O, Morgan GC, Kellerhals R (1984) Quantitative analysis of debris torrent hazards for design of remedial measures. Canadian Geotechnical Journal 21:663–677
Hutter K, Svendsen B, Rickenmann D (1994) Debris flow modeling: a review. Contin Mech Thermodyn 8(1):1–35
King JP (2013) Tsing Shan debris flow and debris flood (GEO Report No. 281). Geotechnical Engineering Office, Hong Kong, p 265
Koo (2017) 3D Debris Mobility Assessment using LS-DYNA (GEO Report No. 325). Geotechnical Engineering Office, Hong Kong, p 90
Kwan JSH (2012) Supplementary technical guidance on design of rigid debris-resisting barriers (GEO Report No. 270). Geotechnical Engineering Office, Hong Kong, p 88
Kwan JSH, Wong LA (2019) A new generation of rigid debris-resisting barriers system in Hong Kong. Proceedings of 2019 International Programme on Landslides Symposium. UNESCO, Paris, pp 7–14
Kwan JSH, Lam HWK, Ng CWW, Lam NTK, Chan SL, Yiu J, Cheuk JCY (2018) Recent technical advancement in natural terrain landslide risk mitigation measures in Hong Kong. HKIE Transactions 25(2):90–101
Lam NTK, Yong ACY, Perera JS, Kwan JSH, Lam HWK, Wong LA (2018a) Flexural response of reinforced concrete barriers subject to boulder impact. Proceedings of ISSMGE Second JTC1 Workshop - Triggering and Propagation of Rapid Flow-like Landslides.
Lam C, Yong ACY, Kwan JSH, Lam NTK (2018b) Overturning stability of L-shaped rigid barriers subjected to rockfall impacts. Landslides 15(7):1347–1357
Lo DOK (2000) Review of natural terrain landslide debris-resisting barrier design (GEO Report No. 104). Geotechnical Engineering Office, Hong Kong, p 91
MGSL (2008) Detailed Study of the 21 August 2005 Debris flow on the natural hillside near Fei Ngo Shan Service Reservoir (GEO Report 233). Geotechnical Engineering Office, Hong Kong, p 123
MLR (2006) Specification of geological investigation for debris flow stabilization. DZ/T 0220-2006. China, National Land Resources Department, p 32 (in Chinese)
Ng CWW, Song D, Choi CE, Koo CH, Kwan JSH (2016) A novel flexible barrier for landslide impact in centrifuge. Géotechnique Lett 6(3):221–225
NILIM (2007) Manual of technical standard for designing sabo facilities against debris flow and driftwood. Technical Note of NILIM No. 365, Natural Institute for Land and Infrastructure Management, Ministry of Land, Infrastructure and Transport, Japan, 73 (in Japanese)
Pun WK, Ho KKS (1996) Analysis of triaxial tests on granitic saprolite performed at Public Works Central Laboratory (GEO Discussion Note No. DN 4/1996). Geotechnical Engineering Office, Hong Kong, p 72
Song D, Choi CE, Ng CWW, Zhou GGD, Kwan JSH, Sze HY, Zheng Y (2019) Load-attenuation mechanisms of flexible barrier subjected to bouldery debris flow impact. Landslides 2019(16):2321–2334
SWCB (2019) “Debris-flow chapter” in Soil and water conservation handbook. Soil and Water Conservation Bureau, Taiwan, p 112
Takahashi T (2007) Debris flow: mechanics, prediction and countermeasures. Taylor & Francis, Leiden, p 448
Vagnon F (2020) Design of active debris flow mitigation measures: a comprehensive analysis of existing impact models. Landslides 17:313–333
VanDine DF (1996) Debris flow control structures for forest engineering. Ministry of Forests, British Columbia, p 68
Volkwein A, Wendeler C, Guasti G (2011) Design of flexible debris flow barriers. Proceedings of the 5th International Conference on Debris-Flow Hazards. Mitigation, Mechanics, Prediction and Assessment, Padua, pp 1093–1100
Watanabe M, Ikeya H (1981) Investigation and analysis of volcanic mud flows on Mount Sakurajima, Japan. Erosion sediment transport measurement. Int Assoc Hydrol Sei Publ, 133, Florence, 245–256
Wendeler C, Volkwein A, McArdell BW, Bartelt P (2018) Load model for designing flexible steel barriers for debris flow mitigation. Can Geotech J 56:893–910
Wong LA, Lam HWK (2019) Study of dynamic soil debris impact load on rigid debris-resisting barriers (GEO Technical Note No. 5/2019). Geotechnical Engineering Office, Hong Kong, p 52
Zhang S, Hungr O, Slaymaker O (1996) The calculation of impact force of boulders in debris flow. Debris Flow Observation and Research, edited by R. Du, Science Press, pp 67-72 (in Chinese)
Acknowledgements
This paper is published with the permission of the Head of the Geotechnical Engineering Office and the Director of Civil Engineering and Development, the Government of the Hong Kong Special Administrative Region.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Lam, H.W.K., Wong, A.L. Experimental and numerical study of dynamic soil debris impact load on reinforced concrete debris-resisting barriers. Landslides 18, 955–966 (2021). https://doi.org/10.1007/s10346-020-01529-w
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10346-020-01529-w