Influence of Slope Shape and Surface Roughness on the Moving Paths of a Single Rockfall

Authors: Iau-Teh Wang, Chin-Yu Lee

Abstract:

Rockfall is a kind of irregular geological disaster. Its destruction time, space and movements are highly random. The impact force is determined by the way and velocity rocks move. The movement velocity of a rockfall depends on slope gradient of its moving paths, height, slope surface roughness and rock shapes. For effectively mitigate and prevent disasters brought by rockfalls, it is required to precisely calculate the moving paths of a rockfall so as to provide the best protective design. This paper applies Colorado Rockfall Simulation Program (CRSP) as our study tool to discuss the impact of slope shape and surface roughness on the moving paths of a single rockfall. The analytical results showed that the slope, m=1:1, acted as the threshold for rockfall bounce height on a monoclinal slight slope. When JRC ´╝£ 1.2, movement velocity reduced and bounce height increased as JCR increased. If slope fixed and JRC increased, the bounce height of rocks increased gradually with reducing movement velocity. Therefore, the analysis on the moving paths of rockfalls with CRSP could simulate bouncing of falling rocks. By analyzing moving paths, velocity, and bounce height of falling rocks, we could effectively locate impact points of falling rocks on a slope. Such analysis can be served as a reference for future disaster prevention and control.

Keywords: Rockfall, Slope Shape, Moving Path, SurfaceRoughness.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1059437

References:

[1] G. P. Giani, "Rock Slope Stability Analysis," Balkema, Rotterdam, pp. 361, 1992.
[2] T. J. Pfeiffer, and T. D. Bowen, "Computer simulation of rockfalls," Bulletin of the Association of Engineering Geologist, vol. 26, pp. 135-146, 1989.
[3] T. J. Pfeiffer, J. D. Higgin, and R. D. Andrew, "Colorado Rockfall Simulation Program," User Manual for Version 2.1- Colorado School of Mines, Golden, CO, 1991.
[4] S. S. Wu, "Rockfall evaluation by computer simulation," Transportation Research Record 1031, TBR, National Research Council. Washington D. C., pp. 1-5, 1984.
[5] A. M. Ritchie,"The evaluation of rockfall and its control," Highway Research Record, No. 17, Washington D.C., pp. 1-5, 1963.
[6] R. M. Ritchie,"Evaluation of rockfalls and its control," Highway Research Record, No. 17, Washington D.C., pp. 13-28, 1963.
[7] H. Wadell,"Volumn shape and roughness of rock particles," Journal of Geology, vol. 40, pp. 443-451, 1932.
[8] A. Azzoni, L.G. Barbera, and A. Zaninetti, "Analysis and prediction of rockfalls using a mathematical model," Int. J.of Rock Mech.Sci. and Geomech. Abstr., vol. 32, No. 7, pp. 709-724, 1995.
[9] Y. Okura, H. Kitahara, T. Sammori, and A. Kawanami, "The effects of rockfall volume on runout distance," Engineering Geology vol. 58, pp. 109-124, 2000.
[10] P. G. Fookes, and M. Sweeney, "Stabilization and control of local rock falls and degrading rock slope," Quarterly J. Engrg. Geology, vol. 9, pp. 37-55, 1976.
[11] I. Statham, "A simple dynamic model of rockfall: some theoretical principles and field experiments," International Colloquium on Physical and Geomechanical Models, pp. 237-258, 1979.
[12] P. Paronuzzi, "Probabilistic approach for design optimization of rockfall protective barriers," Quarterly J. Engrg. Geology, vol. 22, pp. 135-146, 1989.
[13] S. G. Evans, and O. Hungr, "The assessment of rockfall hazard at the base of talus slopes," Can. Geotech. J, vol. 30, pp. 630-636, 1993.
[14] D. Bozzolo, and R. Pamini, "Simulation of rock falls down a valley side," Acta Mech., vol. 63, pp. 113-130, 1986.
[15] T. J. Pfeiffer, and T. D. Bowen, "Computer simulation of rockfalls," Bull. Ass. Engrg. Geology, vol. 26, pp. 135-146, 1989.
[16] A. Azzoni, G. L. Barbera, and A. Zaninetti, "Analysis and prediction of rockfalls using a mathematical model," Int. J.of Rock Mech.Sci. and Geomech. Abstr., vol. 32, No. 7, pp. 709-724, 1995.
[17] A. Azzoni, and M. H. Freitas, "Experimentally gained parameters, decisive for rockfall analysis," Rock Mech. and Rock Engrg., vol. 28, No. 2, pp. 111-124, 1995.
[18] S. G. Evans, and O. Hungr, "The assessment of rockfall hazard at the base of talus slopes," Can. Geotech. J, vol. 30, pp. 630-636, 1993.
[19] Gere, and Timoshenko, Mechanics of Materials, Second Edition, Appendix E, pp. 1-54, 1980.
[20] N. Barton, and V. Choubey, "The shear strength of rock joints in theory and practice," Rock Mechanics, vol. 10, pp. 1-54, 1977.