明挖地下综合管廊施工阶段数值模拟分析

发布时间：2019-01-05 20:10

【摘要】：目前,我国主要一线城市均建有城市地下综合管廊。建设地下综合管廊,利于维修和管理各类城市管线、节约城市建设空间、美化城市景观,是提升城市生活品位的必由之路。在城市化发展的同时,城市人口和城市管线逐渐增多。人们对地下城市综合管廊的使用功能和需求日益增大,地下综合管廊的结构尺寸越来越大、断面形式越来越复杂、施工难度越来越高,对当前新型结构地下综合管廊施工的研究有所裨益。本文以郑州市中原区多层多舱结构地下综合管廊工程为工程实例,使用ABAQUS有限元软件建立了土体、支护结构、管廊主体结构共同作用的三维有限元计算模型。对该工程的基坑开挖和支护、管廊主体浇筑、基坑回填三个施工阶段进行数值分析计算。研究了基坑受力变形机理,并把计算结果与现场监测数据对比分析;在管廊浇筑和基坑回填过程中管廊结构变形和应力变化,并对管廊主体结构进行可靠度分析。研究成果可为类似工程的施工和设计提供参考。研究结果表明:(1)数值计算结果与现场实测结果表现出较好的一致性,说明本文建立的有限元计算模型、各材料本构模型和计算参数的选取是恰当的,数值计算结果在一定程度上能反映基坑开挖过程的变形规律。(2)基坑整体变形呈“凸”型,土体由坑内向坑外隆起,基底土体上涌、基壁向两外侧偏移。在基坑开挖的前期基坑变形不明显,在进行三级放坡开挖时,基坑变形明显增大。(3)地表最大沉降不在基坑边坡顶部,因喷锚支护体系作用,锚钉的箍束骨架作用加固了基坑边坡土体,使得距离基坑边坡顶部较近位置处沉降较小。(4)在管廊主体浇筑阶段,基坑稳定性良好。管廊夹层顶板中间部位处变形最大,方向向下。(5)随着基坑回填施工进行,管廊应力和变形逐渐增大。基坑回填高度大于管廊高度后,对下层管廊应力和变形的影响减小。(6)在管廊混凝土强度和挠度控制条件下,管廊结构可靠度均在安全适用范围之内。
[Abstract]:At present, China's main first-line cities have built urban underground comprehensive pipe gallery. It is the only way to improve the quality of city life by constructing underground comprehensive pipe gallery, which is conducive to the maintenance and management of all kinds of urban pipelines, saves urban construction space and beautifies the city landscape. With the development of urbanization, urban population and urban pipelines are increasing gradually. The use function and demand of underground integrated pipe gallery are increasing day by day. The structure size of underground integrated pipe gallery is becoming larger and larger, the section form is more and more complex, and the construction is more and more difficult. It is beneficial to the study of the construction of the new structure underground comprehensive pipe gallery. In this paper, a three-dimensional finite element model for the interaction of soil mass, support structure and main structure of pipe gallery is established by using ABAQUS finite element software, taking the underground comprehensive pipe gallery project of multi-storey and multi-cabin structure in Zhongyuan District of Zhengzhou City as an engineering example. The excavation and support of the foundation pit, the main pouring of the pipe gallery and the backfilling of the foundation pit are numerically analyzed and calculated. The stress deformation mechanism of foundation pit is studied, and the calculated results are compared with the field monitoring data, and the deformation and stress changes of pipe gallery structure during the process of pipe gallery construction and foundation pit backfilling are analyzed, and the reliability of the main structure of pipe gallery is analyzed. The research results can provide reference for the construction and design of similar projects. The results show that: (1) the numerical results are in good agreement with the field measured results, which indicates that the finite element calculation model, the constitutive model of each material and the selection of calculation parameters are appropriate. The numerical results can reflect the deformation law of the excavation process to some extent. (2) the whole deformation of the foundation pit is "convex", the soil is uplifted from the pit to the outside of the pit, the foundation soil is upwelled, and the foundation wall is shifted to the two sides. In the early stage of excavation, the deformation of foundation pit is not obvious, and the deformation of foundation pit is obviously increased during the third stage of excavation. (3) the maximum surface settlement is not at the top of the slope of foundation pit, because of the effect of shotcrete anchor support system. The hoop skeleton of anchor nail strengthened the soil of the slope of foundation pit, which made the settlement smaller near the top of the slope. (4) the stability of foundation pit was good in the main pouring stage of pipe gallery. The deformation of the middle part of the pipe gallery sandwich roof is the largest and the direction is downward. (5) with the foundation pit backfilling construction, the stress and deformation of the pipe gallery gradually increase. When the backfill height of foundation pit is higher than the height of pipe gallery, the influence on stress and deformation of lower pipe gallery is reduced. (6) under the control of concrete strength and deflection of pipe gallery, the reliability of pipe gallery structure is within the safe and applicable range.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU990.3

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