基于微粒群算法的重力坝坝基多滑面稳定可靠度分析

Reliability analysis on stabtility of gravity dam foundation over multiple sliding planes using PSO

以往混凝土重力坝坝基抗滑稳定可靠度分析大多只研究单滑面或双滑面的情形,但通常的地质条件下,基岩内可能存在多滑面失稳,目前关于重力坝多滑面抗滑稳定可靠度的研究成果相对较少。本文在刚体极限平衡等安全系数法的基础上,提出了基于微粒群算法的重力坝坝基深层多滑面抗滑稳定可靠度计算方法,该方法能够处理非线性隐式功能函数的可靠指标计算问题,即根据可靠指标的几何涵义,将可靠度计算转化为约束优化问题,从而实现智能优化计算。3个算例分析表明,该方法计算工作量少,精度和计算效率高,算法适用性广,能够应用到复杂的坝基多滑面抗滑稳定可靠度计算中。工程实例分析表明,该方法具有较高的实用价值,可为重力坝稳定安全评价方法的深入研究与重力坝结构设计提供新的思路和技术支撑。

Instability of foundation over muhiple sliding planes is a general case occurring in bedrock under most engineering geological conditions of concrete gravity dams. But there are little literatures on extensively researching about this case. For simplication the instability probability was commonly evaluated using models of single or dual sliding plane（s） for the dam foundation. Base on the geometric interpretation of the realiability index, the reliability calculation can be treated as mathematical optimization, so the particle swarm optimization （PSO） can be used logically. A reliability calculating method on the basis of PSO is provided in the paper, which is applied to evaluate the stabiliy reliability index of concrete gravity dana foundation over multiple sliding planes. By camparison with the calculated results by other methods for three testing examples and an actural dam, the method is verified to be accurate, efficient and rational, and can be utilized to the practical complex engineering, for which the performance function for reliablity analysis is nonlinear and implicit. So the method will benefit the further research and provide good technical support on the stabiliy safety assessment and structrual design of gravity dam.