Comparison of Different Methods for Calculating Persistence Based on Monte Carlo Simulation

Discontinuity persistence has always been a hot topic in the field of rock mass engineering, which plays an active role in the evaluation of rock strength and stability. The calculation of persistence based on Monte Carlo simulation is a more widely used and more economical method. At present, the methods of calculating persistence based on Monte Carlo simulation include bandwidth projection method, dynamic programming method and shortest path method. By comparing the three methods through examples, the results show that the persistence values calculated by the three methods are anisotropic; when the projection baseline (or shear, or search) direction is fixed, the persistence values calculated by the bandwidth projection method will continue to increase with the increase of bandwidth, while the persistence values calculated by the dynamic programming method and the shortest path method tend to be stable with the increase of bandwidth. The persistence calculated by dynamic programming method and shortest path method are consistent in different bandwidth. Based on comprehensive analysis and consideration, it is suggested that the shortest path method should be used to determine the recommended value of persistence in engineering practice.