地下连拱结构形状优化的分层演化法

Study on Layer Evolutionary Method in Underground Multiple Arch Structure Optimization

作者运用弹塑性有限元程序计算地下连拱结构和上覆土体的应力、应变状态,将地面不均匀沉降最小作为设计目标,将支撑结构的形状优化结合到土体单元的演化过程中,同时进行支撑结构的形状优化与土体单元的演化。在整个演化程序的进行中,所用有限单元既可以参与演化,又可以参与支撑结构的形状优化。工程实例表明文中提出的分层演化优化法速度快,对地下连拱结构形状优化是个新的选择,满足不均匀地面沉降最小的拱高随覆土厚度的增加而增加,并提出了拱高与覆土厚度的近似最优比值。

Stress status and strain status of underground multiple arch structure and the overlying soil were analyzed with elasto-plastic FEM, and the minimization of ground surface non-uniform settlement was taken as design objective. The shape optimization of supporting structure was combined with the evolution of overlaying soil, both of them are carried out at the same time. During the evolution process, the used finite element participated the evolution and the shape optimization of supporting structure. The example shows that the speed of layer evolutionary optimization method is high, and that the proposed method is a new approach to the shape optimization of underground multiple arch structure. The height of arch satisfying the minimization of ground surface non-uniform settlement is increasing with the depth of overlying soil, furthermore, a approximate optimum ratio of arch height to the depth of overlying soil is proposed.