动态自适应遗传算法在桩锚支护结构优化设计中的应用

Application of dynamic adaptive genetic algorithm in the optimization design of pile-anchor retaining structures

在保证基坑稳定性的条件下,为了提高桩锚支护结构经济性,建立了桩锚支护结构的优化设计模型,并对其支撑道数、桩径、嵌固深度和混凝土强度等级等设计参数做了敏感性分析,在此基础上确定各个优化设计参数的合理取值范围,为桩锚支护优化提供了约束条件。针对传统的遗传算法在迭代过程中出现过早地收敛到局部最优解和在最优值附近收敛速度慢等缺点,提出了动态自适应技术改进遗传算法的新算法(动态自适应遗传算法,DAGA)。工程实例分析表明,动态自适应遗传算法不受设计空间可微性、连续性等限制,适合于求解具有离散设计变量的桩锚支护工程;不仅有较好的收敛性,而且在求解时间上具有一定的优势。

In order to reduce the cost of pile-anchor retaining structures in the condition of ensuring stability of foundation pit,the optimization model was established.Sensitivity analysis of design parameters were carried out,such as layer number of bracing,pile diameter,concrete strength grade,and etc.On the basis of above analyses,the reasonable ranges of preliminary values of optimization design parameters were given,which provided constraint conditions for the optimization of the pile-anchor retaining.In view of disadvantages of traditional genetic algorithm,such as early converge to local optimal solution and slow convergent speed near optimal value,and etc,a new algorithm（dynamic adaptive genetic algorithm,DAGA） was put forward,and the algorithm was established by applying dynamic adaptive technology to improve traditional genetic algorithm.Engineering example analysis shows that the dynamic adaptive genetic algorithm not only solves the problems of the differentiability and continuity of design space,but also is particularly suitable for optimization design of the pile-anchor retaining structures with discrete design variables.The dynamic adaptive genetic algorithm presented has a better convergence as well as the advantages of the solution time.