基于序列二次规划算法的加筋土挡墙布筋方案优化设计

Optimal Design of Geosynthetics-Reinforced Wall Based on Sequential Quadratic Programming Method

基于室内模型试验,采用控制变量法,初步研究了筋带宽度、筋带长度、筋带水平间距、筋带垂直间距对加筋土挡墙承载力和稳定性的影响.在模型试验的基础上,采用序列二次规划算法(SQP),以最小筋带用量为控制目标,以不发生任何模式的破坏为约束条件,建立非线性约束规划的优化设计数学模型,利用MATLAB优化工具求得最优解,并进行室内模型试验验证,试验结果与优化结果吻合较好.结果表明,加筋土挡墙的承载能力和稳定性与筋带总量并非成正比关系.在保证竖向承载能力不变的情况下,利用SQP算法优化后的筋带布置,可节省筋带用量约1/4,水平承载能力提高约2/5.

Based on laboratory model test, the control variable method was applied to investigate the effect of reinforcement width, length, and horizontal and vertical spacing between reinforcement materi- al on the bearing capacity and stability of the retaining wall. Based on the model test, the sequential quadratic programming （SQP） algorithm was used and the minimum of reinforcement amount was cho- sen as the control target. The constraint condition was chosen without any mode of failure to establish the nonlinear constrained programming mathematical model of optimization design. The optimal solution was obtained using the MATLAB optimization tools and the model test was operated to confirm the va- lidity of the optimal solution. The test results matched the optimized results very well. It is can be drawn out that the bearing capacity and stability of the reinforced retaining wall are not increased linear- ly with the increase of the reinforcement amount. After optimization, the vertical load of the reinforced retaining wall keeps the same while the horizontal load nearly increase 2/5 of the one before optimiza- tion. The total amount of reinforcement decrease 1/4 of the one before optimization.