浅埋暗挖拱顶直墙结构过街地道数值模拟分析

1.西安科技大学 建筑与土木工程学院,陕西 西安 710054; 2.杭州市城建设计研究院,浙江 杭州 310020

城市过街地道; 浅埋暗挖法; 拱顶直墙结构; 数值模拟

Numerical simulation analysis of crossing-street tunnels with vault straight wall structure constructed by shallow tunneling method
YUN Yong-feng1,XIONG Zhi-hui1,XIONG Chu-ming2

(1.College of Civil and Architectural Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Architectural & CML Engneering Design Institute Co.,Ltd., Hangzhou 310020,China)

urban crossing-street tunnel; shallow tunneling method; vault straight wall structure; numerical simulation

DOI: 10.13800/j.cnki.xakjdxxb.2016.0209

备注

城市过街地道多采用浅埋暗挖法施工,它的突出优势在于能最大限度地减少交通干扰、管线及板涵的迁移改建。城市过街地道对地表沉降的要求比较严格,选择合理的隧道断面形式对控制地表沉降具有很大意义。采用MIDAS/GTS软件建模进行有限元分析,对拱顶直墙与平顶直墙结构变形进行了对比,分析施工分部开挖拆除临时支撑后衬砌内力的变化。对模型计算结果进行分析并结合工程环境给出合理的施工建议。结果 表明:浅埋暗挖过街地道顶部覆土层过薄,为控制地表下沉需对地层进行加固处理; 相同条件下拱顶直墙结构受力变形小于平顶直墙结构; 底板弯矩变形较大,二次衬砌结构施工可适当增加底板厚度; 拆除临时支撑后初衬轴力与弯矩增大约1~2倍。可为浅埋暗挖拱顶直墙过街地道衬砌内力研究提供依据,也可为实际工程施工提供参考。

Most of the urban crossing-street tunnels are constructed with shallow tunneling method,whose outstanding advantages are that it can minimize traffic interference and the migration and reconstruction of pipeline and slab culvert.Urban crossing-street tunnels have relatively strict requirements regarding surface subsidence,and choosing reasonable shape of tunnel's section has great significance for controlling the surface subsidence.FEM analysis on model established with MIDAS/GTS software has compared the structural deformation of vault straight wall and flat-roofed straight wall,and analyzed the change of internal force of lining after demolition of the temporary support during partial excavation in the construction.Reasonable construction suggestions are given through the analysis of calculation results of the model and combining with the engineering environment.The results show that:because the soil covering on the top of the crossing-street tunnel constructed with the shallow tunneling method is too thin,it is necessary to reinforce the formation to control the surface subsidence; under the same condition,the deformation of the vault straight wall structure is smaller than that of the flat-roofed straight wall structure; the deformation of the base slab's moment is relatively bigger,so the secondary lining structure construction can appropriately increase the thickness of the base slab; after the demolition of the temporary support,the axial force of the first lining and the bending moment increase about 1~2 times.The research provides a reference for practical engineering construction.