Probabilistic design optimization and simplified geotechnical risk analysis for large open pit excavations

A probabilistic geotechnical design optimization framework for large open pit excavations is proposed in the present work. An appropriate objective function is formulated in terms of normalized cost of excavation, while the overall slope angle constitutes the decision variable. Probability of slope's failure is computed via Monte Carlo simulations. Optimization curves identifying the optimum slope's angle are developed for different risk and volume factors. For illustrative purposes, a typical example of a surface lignite mine is analyzed and results are thoroughly discussed. The suggested methodology can be used as a complementary tool in the decision analysis process of similar projects.