考虑土体超固结的船坞深基坑开挖与邻近桩基的相互影响研究

发布时间：2018-06-01 00:01

本文选题：应力路径 + 超固结　；参考：《广西大学》2015年硕士论文

【摘要】：当前,我国城市建设正处于高速发展时期,出现了—大批深基坑工程。对于这些重大的基坑工程,用常规的土工加载试验强度参数进行基坑工程设计是不合适的,因此,迫切需要引入考虑土体卸荷应力路径的设计计算方法,以指导设计和施工。而船坞基坑周围桩基密集,因此在进行船坞基坑工程设计和施工时必须考虑到基坑开挖与邻近桩基的相互影响。本文就是以此为背景,分析基坑开挖与邻近桩基的相互影响,主要包括以下几个方面的内容：(1)借助GDS三轴试验系统,模拟基坑开挖过程中土体的实际应力路径,提出了超固结软土的K0系数修正计算公式。(2)对比分析了基坑开挖过程中,考虑与不考虑土体超固结比变化的计算结果发现,考虑超固结比变化影响的墙体侧移,最大地表沉降,邻近桩基位移,桩基最大弯矩分别比后者的结果小约10%以上。(3)深基坑开挖的数值模拟中考虑超固结比变化的影响能较好的反应开挖面以下土体的卸荷。可见,在深基坑工程的数值模拟中考虑土体超固结比的变化是很有必要的。(4)考虑土体超固结比变化的影响,进行了基坑对邻近桩基的相互影响研究。分析了基坑—桩间距、桩刚度、开挖深度、桩径等不同影响因素下基坑对邻近桩基位移和弯矩的影响。并对影响因素敏感性大小作了分析,以期为有关的设计和施工提供参考。
[Abstract]:At present, China's urban construction is in a period of rapid development, and a large number of deep foundation pit projects have emerged. For these important foundation pit projects, it is not appropriate to use the strength parameters of the conventional geotechnical loading test to design the foundation pit. Therefore, it is urgent to introduce the design and calculation method considering the unloading stress path of soil to guide the design and construction. The pile foundation around the dock foundation pit is dense, so the interaction between excavation and adjacent pile foundation must be taken into account in the design and construction of dock foundation pit. Based on this background, this paper analyzes the interaction between excavation of foundation pit and adjacent pile foundation, which mainly includes the following contents: 1. With the help of GDS triaxial test system, the actual stress path of soil in the excavation process of foundation pit is simulated. The calculation formula of K _ 0 coefficient correction for overconsolidated soft soil is put forward. The calculation results of considering and not considering the change of soil overconsolidation ratio in excavation process are compared and analyzed. It is found that the wall with the influence of over-consolidation ratio changes is sideways and the maximum surface settlement is obtained. Next to the displacement of pile foundation, the maximum bending moment of pile foundation is less than 10% or more than the result of the latter.) in the numerical simulation of deep foundation pit excavation, considering the influence of the change of overconsolidation ratio, the unloading of soil below the excavated surface can be well reflected. Therefore, it is necessary to consider the change of soil overconsolidation ratio in the numerical simulation of deep foundation pit engineering. The influence of different factors, such as the distance between foundation pit and pile, the stiffness of pile, the depth of excavation and the diameter of pile, on the displacement and bending moment of adjacent pile foundation is analyzed. The sensitivity of influencing factors is analyzed in order to provide reference for related design and construction.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU753

【参考文献】