基于改进萤火虫优化算法和考虑空间变异特性的边坡最小安全系数确定研究

在基本萤火虫算法中引入“短视”策略，结合一典型不排水边坡短期稳定问题，考虑土体材料的空间变异特性，构建相应参数的随机场，探讨了萤火虫个体数目N、移动步长β对萤火虫算法搜索效率的影响。结果表明:在其他条件相同的前提下，引入“短视”策略的萤火虫算法较未采取“短视”策略的萤火虫算法结果标准差要小，说明“短视”策略可以提高萤火虫算法的寻优能力；萤火虫个体数目N的增加也会提高算法的寻优能力，但是算法的计算时间T与N^2.1成正比；从安全系数平均值角度来看，移动步长β的合理取值建议介于0~2之间；相同参数设置下萤火虫算法在波动范围较大时搜索到的安全系数标准差较之波动范围较小时的标准差要小，证明了波动范围增大后，边坡稳定最小化安全系数这一优化问题的复杂程度减弱；在考虑土体材料空间变异特性时，要变换算法的参数或者尝试不同的优化算法，以确保找到最小的安全系数及失稳模式。

Improved Firefly Optimization Algorithm for Location of Minimum Factor of Safety Considering Spatial Variability

The short-sighted strategy was introduced into the original firefly algorithm, and a typical short-term stability problem of undrained slope was considered. The random field of corresponding parameters was constructed considering the spatial variability of soil material. Finally, the influence of the number of firefly individuals N?and the moving step β on the search efficiency of the algorithm was discussed. The results show that under the same other conditions, the standard deviation of the firefly algorithm results with the short sighted strategy is smaller than that of the firefly algorithm without the short-sighted strategy, which indicates that the short-sighted strategy can improve the searching ability of the algorithm. Increasing the number of firefly individuals N will also improve optimization ability of the algorithm, but the calculation time T of the algorithm is proportional to N^2.1?From the point of view of the average safety factor, the reasonable value of the moving step β is between 0 and 2. Under the same parameters, the standard deviation of the safety factor searched by the firefly algorithm with larger fluctuation range is smaller than that with smaller fluctuation range. It is proved that the complexity of the optimization problem of minimizing the safety factor of slope stability decreases with the increase of the fluctuation range. Considering the spatial variability characteristics of soil materials, the parameters or different optimization algorithms should be transformed to ensure finding the minimum safety factor and instability mode.