论文部分内容阅读
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。
Urban overpasses are mostly constructed by shallow burying and undercutting. Its outstanding advantages lie in minimizing traffic disturbance, and the relocation and reconstruction of pipelines and plate culverts. Urban street tunnels on the surface subsidence more stringent requirements, the choice of a reasonable section of the tunnel surface control of ground subsidence is of great significance. The finite element analysis was carried out by using MIDAS / GTS software to compare the deformation of the straight wall and the flat-roofed straight-wall structure. The analysis of the change of lining internal force after temporary support was carried out in the excavation of the construction section. The model calculation results are analyzed and the reasonable construction suggestions are given based on the engineering environment. The results show that the overburden of overburden is too thin, and the strata should be reinforced to control the surface subsidence. Under the same conditions, the stress deformation of the straight wall structure is less than that of the flat-topped straight wall structure. The construction of large and secondary linings may increase the thickness of the soleplate properly. After the temporary support is removed, the initial axial force and bending moment increase about 1 ~ 2 times. It can provide the basis for the research on the internal force of tunnel lining in shallow buried burial vault, and also provide a reference for the actual construction.