Stochastic analysis of rock fall dynamics on quarry slopes

• Computer analysis of full-scale droptests carried out at a number of quarry faces.
• Discussion of detailed results from 277 tests in Austria and 34 tests in Canada.
• First order predictions using a simple dynamic model with a single set of input parameters.
• Evaluation of the basic hazard dimensions “impact distance” and “runout distance”.

In order to study rock fall dynamics, a research project conducted by the Vienna University of Technology and the Austrian Central Labour Inspectorate (Federal Ministry of Labour, Social Affairs and Consumer Protection), 589 full-scale drop tests were carried out in different quarries, recording key parameters of the rock fall trajectories. Similar drop tests were conducted by a team from the University of British Columbia and the B.C. Ministry of Transportation and Highways at a quarry site in British Columbia, Canada. In this paper, detailed results of 277 tests at three sites in Austria and 34 tests at the site in Canada are described. The tests involved a total of 311 boulders ranging from 0.18 to 1.8 m in diameter and from 0.009 to 8.1 Mg in mass. The geology of the different sites included strong rock belonging to igneous, metamorphic and volcanic types. The results of the tests are compared to computer analyses conducted with a new dynamic model, using a single set of parameters for all the sites. In general, reasonable stochastic approximations of the rock fall trajectories have been obtained in all dimensions, including runout, bounce heights and velocities. The approximations are compared to the measured data in terms of median, 95% and maximum values. The results of the comparisons indicate that approximate first-order predictions, using a single set of input parameters, are possible and can be used to aid practical hazard and risk assessment.