|Alternative Title||The stability and prediction of the underground corridor in Wuhan|
|Place of Conferral||兰州|
|Keyword||基坑开挖 稳定性分析 土压力 数值模拟FLAC3D|
本文以武汉市某步行街地下走廊基坑开挖为研究背景，首先进行基坑开挖区域工程地质条件的详细调查，重点包括：地形地貌、地层岩性、地质构造、水文地质条件以及气象条件等方面。同时在基坑开挖区域进行了岩土取样，并对所取试样的物理力学性质进行了检测分析。在获得了基坑开挖区域所取土样物理力学性质的基础上，对比了朗肯土压力理论和库仑土压力理论在土压力计算方面的适用性及在土压力计算精确性方面的优缺点，为后续分析打下良好的基础。结合朗肯土压力理论和库仑土压力理论，根据基坑稳定性计算分析原理，分析了地下走廊开挖过程中的基坑稳定性，结果表明：基坑整体稳定性，基坑抗隆起稳定性，基坑抗倾覆稳定性均满足要求。简单的理论计算不能全面、准确地反映在取土开挖过程中基坑的应力分布状况和位移变化情况。因此，在上述工作的基础上，利用数值模拟软件FLAC3D对基坑开挖的应力分布状况及变形状况进行了详细的计算分析。该计算方法区别于有限元分析方法：模拟过程是基于差分法进行计算，差分法能够有效解决边坡稳定性以及基坑整体稳定中的大变形问题。数值模拟结果如下：(1) 对于未设支护结构的基坑进行了数值模拟分析，发现基坑坑壁的变形较大，变形量明显影响基坑的稳定性。(2) 分析了基坑开挖过程中钢筋混凝土支撑对基坑坑壁稳定性的影响，重点研究了混凝土支撑结构的截面尺寸变化对基坑支护效果的影响。发现在钢筋混凝土支撑结构形式不变的条件下，单方面增大混凝支撑的截面尺寸对基坑支护效果的影响较小。在进行基坑内支撑结构设计时，不应单纯增加混凝土支撑的截面尺寸以提高基坑的稳定性。上述计算结果对于该基坑工程的后期施工以及安全运营可以提供指导，为工程后期顺利进行奠定良好的基础。
With the development of Chinese economy, urban population is increasing, and how to make good use of the urban space becomes an important issue. In the development of all major cities, high rises, subway and underground shopping malls have become the necessary choice for the development of large cities in the country, among which the construction of subway projects and underground shopping malls belong to the category of underground engineering. In the underground engineering, the excavation of the foundation pit is a problem that every underground project will face.
This paper has carried out careful investigation for engineering geological condition taking a pedestrian street corridor underground excavation in Wuhan as the research background. It mainly includes: topography, lithology, geological structure, hydrogeological conditions and weather conditions, etc. Meanwhile, the sample of soil has also been carried out and the physical properties are also tested.Based on the physical properties, the paper also analyzed the advantages and disadvantages of the Rankine earth pressure theory and Coulomb earth pressure in order to lay a good foundation for the subsequent analysis. Then, combined with these 2 theories, the paper analyzed the stability of the foundation pit based on the stability calculation. The result proves that the stability of the foundation pit can meet the standard.However, the simple calculation theory can’t reflect the displacement and stress distribution of the foundation pit in the excavation accurately and fully. Therefore, based on the research mentioned above, this paper used FLAC3D to make a detailed calculation for stress distribution and transformation in the excavation of the foundation pit. This kind of calculation is different from the finite element analysis method, that is, the simulation process is based on the difference method, and it can solve the stability of foundation pit. Numerical simulation is at the scene of the accurate exploration results and the soil mechanics parameter. The results are as following:(1) A numerical simulation analysis for foundation pit without supporting structure was made, and it’s found the deformation of foundation pit walls is larger, which can significantly influence the stability of the foundation pit deformation.(2) The influence of the stability of the reinforced concrete supporting of foundation pit wall was analyzed, and .we focuses on the effect of section size of foundation pit. It is found in the reinforced concrete support structure under the condition of invariable, the effect of increasing the size of concrete support of is small, and when making the structure design of supporting in the foundation pit, the size of the concrete support shouldn’t be increased to improve its stability.The calculation results can provide guidance for the later construction and safety operation of foundation pit engineering. Also this work can lay a good foundation for the later engineering.
|刘满. 武汉某地下走廊开挖稳定性计算及预测分析[D]. 兰州. 兰州大学,2016.|
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