软弱围岩公路隧道衬砌结构形式拓扑优化

Topological Optimization for Highway Tunnel Lining Structure Pattern of Soft-Wreak Surrounding Rocks

首次基于连续体的结构优化理论和有限元方法,采用简化的假定条件,应用拓扑优化理论,以应变能最小即刚度最大为约束条件,成功对不同应力场软弱围岩公路隧道衬砌结构体进行了结构优化。单拱隧道衬砌结构拓扑优化结果表明:不同的应力场和不同的围岩强度,衬砌结构的断面型式和厚度差别较大;随着侧压力系数的增大,衬砌结构断面高跨比应越来越小;衬砌结构拱顶的厚度越来越大,仰拱的作用也越来越明显。连拱隧道衬砌结构的拓扑优化结果除得出与上述单拱隧道相似的结论外,还表明随着围岩强度的降低和侧压力系数的增大,直中墙型式越来越优于曲中墙。

Through the application of topology optimization and FEM theory,adopted simplicity assumption,based on the principle of the least strain energy equivalent to the most stiffness,the structure forms of single-arch and multiple-arch tunnel lining are optimized for the first time.The result of single-arch tunnel structure shows that the difference of the cross section pattern and thickness of the lining work structure are bigger in different stress field and different surrounding rock intensity.With the increasing of lateral pressure coefficient,the height-span ratio of the cross section lining work structure should be smaller and smaller,the arch thickness of lining work structure should be bigger and bigger,the function of the inverted arch also should be more and more obvious.The topological optimization result of multiple-arch tunnel structure demonstrate similar conclusion with the single-arch tunnel above,besides to this,it also indicated that along with reducing of the surrounding rock intensity and increasing of lateral pressure coefficient,the straight central wall pattern is more and more excellent than three-layer curved middle wall.