基于蒙特卡洛模拟计算连通率不同方法比较研究

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

结构面连通率一直是岩体工程领域研究的热点课题,其在评价岩体强度及稳定性方面都发挥着积极作用。而基于蒙特卡洛模拟计算连通率是应用较为广泛且更具经济性的方法。目前,基于蒙特卡洛模拟计算连通率的方法包括带宽投影法、动态规划法和最短路径法。通过举例比较研究三种方法,结果表明,三种方法计算所得连通率值均表现为各向异性;而在投影基线(或剪切、或搜索)方向一定,带宽投影法计算所得连通率值会随着带宽的增大持续增大,而动态规划法和最短路径法计算所得连通率值均是在带宽增大达到一定程度后趋于稳定;且动态规划法和最短路径法计算所得连通率值在不同带宽时均较为一致。综合分析考虑,建议在工程实践中采用最短路径法分析确定连通率建议值。

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.