GM  Vol.3 No.1 , January 2013
Assessment of Rockfall Hazard along the Road Cut Slopes of State Highway-72, Maharashtra, India
Abstract: Rockfall is a major problem in high hill slopes and rocky mountainous regions and construction of highways at these rockfall prone areas often require stable slopes. The causes of rockfall are presence of discontinuities, high angle cut slopes, heavy rainfall, and unplanned slope geometry etc. Slope geometry is one of the most triggering parameters for rockfall, when there are variations in slope angle along the profile of slope. The Present study involves rockfall hazard assessment of road cut slopes for 15 km distance starting from Mahabaleshwar town along State Highway-72 (SH-72). The vertical to subvertical cut slopes are prone to instability due to unfavorable orientation of discontinuities in slope face of weathered and altered basaltic rockmass. The predominant type of instability has been found as wedge type failure involving medium to large size blocks. In order to investigate the existing stability conditions, analyses were carried out at two locations under different slope conditions. The kinematic analysis was performed using stereographic projection method. RockFall 4.0 numerical simulator software was used to calculate the maximum bounce heights, total kinetic energies and translational velocities of the falling rockmass blocks, and a comparative analysis is presented with increasing the mass of blocks and height of the slope. The result of numerical analysis shows that varying slope angle geometry creates more problems as compared to the mass of blocks in the scenario of rockfall.
Cite this paper: M. Ahmad, R. Umrao, M. Ansari, R. Singh and T. Singh, "Assessment of Rockfall Hazard along the Road Cut Slopes of State Highway-72, Maharashtra, India," Geomaterials, Vol. 3 No. 1, 2013, pp. 15-23. doi: 10.4236/gm.2013.31002.

[1]   D. M. Cruden and D. J. Varnes, “Landslide Type and Processes,” In: A. K. Turner and R. L. Schuster, Eds., Landslides: Investigation and Mitigation, National Academy Press, Washington DC, 1996, pp. 36-75.

[2]   D. J. Varnes, “Slope Movement Types and Processes,” In: R. L. Schuster and R. J. Krizek, Eds., Landslides, Analysis and Control, National Academy of Sciences, 1978, pp. 11-33.

[3]   H. Chen, R. Chen and T. Huang, “An Application of an Analytical Model to a Slope Subject to Rockfalls,” Bulletin of the Association of Engineering Geologists, Vol. 32, No. 4, 1994, pp. 447-458.

[4]   K. Lee and G. Elliott, “Rockfall: Application of Computer Simulation to Design of Preventive Measures,” Planning, Design and Implementation of Debris Flow and Rockfall Hazards Mitigation Measures, Association of Geo-Technical Specialists & Hong Kong Institution of Engineers, Hong Kong, 1998.

[5]   F. Guzzetti, G. Crosta, R. Detti and F. Agliardi, “STONE: A Computer Program for the Three Dimensional Simulation of Rock-Falls,” Computers and Geosciences, Vol. 28, No. 9, 2002, pp. 1079-1093. doi:10.1016/S0098-3004(02)00025-0

[6]   Itasca, “Itasca Software Products—FLAC, FLAC3D, UD-EC, 3DEC, PFC2D/3D,” Itasca Consulting Group, Inc., Minneapolis, 2010.

[7]   RocScience, “RockFall Software for Risk Analysis of Falling Rock on Steep Slope,” RocScience Inc., Toronto, 2000.

[8]   J. Mahoney, J. D. Macdougall, G. W. Lugmair, A. V. Murali, M. S. Das and K. Gopalan, “Origin of the Deccan Trap Flows at Mahabaleshwar Inferred from Nd and Sr Isotopic and Chemical Evidence,” Earth and Planetary Science Letters, Vol. 60, No. 1, 1982, pp. 47-60. doi:10.1016/0012-821X(82)90019-X

[9]   I. Kaneoka and H. Haramura, “K/Ar Ages of Successive Lava Flows from the Deccan Traps, India,” Earth and Planetary Science Letters, Vol. 18, No. 2, 1973, pp. 229-236. doi:10.1016/0012-821X(73)90061-7

[10]   J. E. Beane, C. A. Turner, P. R. Hooper, K. V. Subbarao, and J. N. Walsh, “Stratigraphy, Composition and Form of the Deccan Basalts, Western Ghats, India,” Bulletin of Volcanology, Vol. 48, No. 1, 1986, pp. 61-83. doi:10.1007/BF01073513

[11]   T. Konda, “Deccan Basalts at Mahabaleshwar, India,” Contributions to Mineralogy and Petrology, Vol. 32, No. 1, 1971, pp. 69-73. doi:10.1007/BF00372234

[12]   Z. X. Peng, J. J. Mahoney, P. R. Hooper, C. Harris and J. E. Beane, “A Role for Lower Continental Crust in Flood Basalt Genesis? Isotopic and Incompatible Element Study of the Lower Six Formations of the Western Deccan Traps,” Geochimica et Cosmochimica Acta, Vol. 58, No. 1, 1994, pp. 267-288. doi:10.1016/0016-7037(94)90464-2

[13]   C. W. Devey and P. C. Lightfoot, “Volcanological and Tectonic Control of Stratigraphy and Structure in the Western Deccan Traps,” Bulletin of Volcanology, Vol. 48, No. 4, 1986, pp. 95-207. doi:10.1007/BF01087674

[14]   B. P. Radhakrishna and R. Vaidyanadhan, “Geology of Karnataka,” Geological Society of India, Bangalore, 1994.

[15]   M. Widdowson and K. G. Cox, “Uplift and Erosional History of the Deccan Traps, India: Evidence from Laterites and Drainage Patterns of the Western Ghats and Kon-kan Coast,” Earth and Planetary Science Letters, Vol. 137, No. 1-4, 1996, pp. 57-69. doi:10.1016/0012-821X(95)00211-T