某地铁车站深基坑排桩支护方案研究

发布时间：2018-05-25 15:31

本文选题：深基坑 + 支护结构　；参考：《河南工业大学》2017年硕士论文

【摘要】：随着城市交通压力的增大,越来越多的城市都陆续开通了地铁,而地铁车站往往较深,所以基坑支护的安全和稳定便显得尤为重要。基坑工程是一门理论性和实践性都很高的学科,其涉及领域也相当广泛,虽然近些年,我国越来越多的人开始投身于基坑支护领域,但由于我国在该领域起步相对较晚,基坑在进行结构选型等方面还存在一些问题,设计施工中都还存在一些不太合理的情况。本文以郑州某地铁车站为依托,通过对该车站所处场地的水文地质等条件进行分析,结合不同围护结构优缺点及使用条件,最终选择排桩加钢支撑这种支护方式,通过对该工艺施工过程中重点难点进行分析,找到解决不同施工问题的方法。利用理正软件对该基坑工程进行结构断面计算,并对基坑的整体稳定性、抗隆起、抗倾覆等进行验算,然后通过手算对支护结构中的围檩、冠梁、挡土墙和立柱进行设计计算,并对钢支撑进行校核,对车站主体抗浮进行验算,从而保证该基坑支护方案的合理性,通过研究发现,排桩加内支撑方式适用于该类场地的基坑支护工程中。在研究过程中主要得出如下结论:(1)基坑在开挖过程中,围护结构会发生水平位移,当基坑开挖至坑底时,最大位移往往发生在坑底上一定距离处,大概在离桩顶五分之二桩长处。(2)钢支撑的支撑刚度对排桩变形影响较大,支撑刚度主要跟钢支撑的长度等因素有关,钢支撑长度较短时,其支撑刚度较大,排桩结构变形会相对较小,所以在基坑开挖时,应尽量选择较短的钢支撑。(3)支护结构的嵌固深度对基坑支护效果及周围土体沉降有一定影响,但当嵌固深度达到设计值之后,再次增加嵌固深度对减小结构受力及周围土体沉降无明显效果,反而会增加施工难度,增大施工造价。
[Abstract]:With the increasing of urban traffic pressure, more and more cities have opened subway, and subway stations are often deeper, so the safety and stability of foundation pit support is particularly important. Foundation pit engineering is a highly theoretical and practical subject, which involves a wide range of fields. Although in recent years, more and more people in our country began to participate in the field of foundation pit support, but our country started relatively late in this field. There are still some problems in structure selection of foundation pit, and some unreasonable conditions exist in design and construction. Based on a subway station in Zhengzhou, by analyzing the hydrogeological conditions of the station, combining with the advantages and disadvantages of different retaining structures and using conditions, this paper finally chooses the supporting method of row pile plus steel support. Through the analysis of the key points and difficulties in the process of construction, the methods of solving different construction problems are found. The structural cross-section of the foundation pit is calculated by using the software of Lizheng, and the overall stability, anti-uplift and anti-overturning of the foundation pit are checked, and then the purlin, crown beam, retaining wall and column in the supporting structure are designed and calculated by hand calculation. By checking the steel braces and checking the main body of the station against floating, the rationality of the foundation pit support scheme is ensured. Through the research, it is found that the method of row pile plus inner bracing is suitable for the foundation pit support engineering of this kind of site. In the course of the research, the following conclusions are drawn: (1) during the excavation of the foundation pit, the retaining structure will have horizontal displacement. When the foundation pit is excavated to the bottom of the pit, the maximum displacement often occurs at a certain distance on the bottom of the pit. It is estimated that the supporting stiffness of the steel bracing with 2/5 piles off the top of the pile has a great influence on the deformation of the row piles. The support stiffness is mainly related to the length of the steel support, and when the steel support length is shorter, the support stiffness is larger. The deformation of pile row structure will be relatively small, so during excavation of foundation pit, the embedded depth of steel bracing should be chosen as far as possible, which has certain influence on the supporting effect of foundation pit and the settlement of surrounding soil, but when the embedded depth reaches the design value, Once more, increasing the embedded depth has no obvious effect on reducing the stress of the structure and the settlement of surrounding soil, but will increase the difficulty of construction and increase the construction cost.
【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】：TU753

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