【作者】 李晓；

【导师】 申翃；

【作者基本信息】 武汉理工大学 ， 土木工程， 2018， 硕士

【摘要】 在改革开放带来的红利下,城市现代化的进程日益加快,许多深、大基坑开始逐渐出现在岩土工程工作者的视野中。深基坑支护作为一种临时性结构,目的是在保证安全、可靠的前提下为主体结构的施工服务。综合现有的基坑支护方式来看,在我国中心城区处理深、大基坑的一般方式多为内支撑、桩锚体系、双排桩等支护型式。这些支护型式都有其各自不可替代的优势,但也有它们自身的局限性。在当今社会提倡环保、高效节约成本的大环境下,对传统的支护型式做出改进,不断的探索并提出新的支护型式以满足设计、施工和建筑行业大环境的需要则是一种势在必行的趋势。本文正是基于这样的一个趋势和需求,在综合如今主流支护型式的优缺点后,提出了一种新型的支护结构——剪力键,并详细的设计了其各部位的布置型式和具体思路,期望解决现有支护存在的问题并在一定适用条件下替代它们。本文在提出剪力键结构后,根据实际工程中支护桩的设计型式,对所提出的新型支护结构进行了模型试验。详细的制定了试验方案,将传统的悬臂桩体系与新提出的剪力键体系进行了试验对比,分析两种支护结构在相同开挖条件下的工作性状,从桩顶位移大小、桩身弯矩分布规律、以及结构的最大弯矩值等多方面去探究和验证剪力键结构优良的支护效果。通过试验所得数据结果,对剪力键支护体系的工作机理进行了一定程度的阐述。为了使笔者所提出的新型支护方式更好的与实际工程对接,也为了能为今后的研究提供更多的理论依据,本文还使用Midas GTS NX软件对整个试验过程进行了有限元仿真模拟,更加全面的探索了该结构的整体支护效果,利用试验所用的材料参数建模,不仅可以得到模型试验的成果趋势,还可以探究剪力键在支护时坑顶的沉降和坑底的隆起规律。完善了该模型的研究,也对试验所得的成果进行了验证和补充。试验及有限元计算结果表明,在同样开挖条件下,新型剪力键支护体系的位移更小,桩身最大弯矩更小,隆起值和沉降值均小于悬臂桩体系。意味着剪力键体系有着更大的支护深度,在实际工程中用更小的桩径和配筋即可满足设计要求,更加安全和节约造价。最后总结了本文研究工作,并对后续研究方向进行了展望。更多还原

【Abstract】 Under the dividend brought by reform and opening up,the process of urban modernization is accelerating.Many deep and large foundation pits are gradually appeared in geotechnical engineering field of vision.The deep foundation pit support is a temporary structure.And the purpose is to serve the construction of the main structure under the premise of ensuring the safety and reliability.Considering the existing supporting methods of foundation pit,the general ways to deal with deep and large foundation pit in our central city are mostly like internal support,pile anchor system and double row piles.These types of support have their own irreplaceable advantages,but they also have their own limitations.Nowadays,we advocate environmental protection,efficient and cost saving.It is imperative for us to improve the traditional support types,and constantly explore and propose new supporting forms to meet the needs of the design,construction and the whole environment of construction industry.Under such a trend and demand,this paper puts forward a new type of retaining structure--shear bond supporting system.The layout of the various parts of this specific ideas and detailed thought have been designed in tend to solve the existing problems of traditional support and to replace them in applicable conditions.After the shear bond structure is put forward,a model test of the new support structure is carried out according to the design type of the supporting pile in the actual project.The detailed test scheme was established.The traditional cantilever pile system and new shear bond system are compared in the same excavation work traits.We have explored and verified the excellent supporting effect of shear key structure from the displacement of pile top,the distribution law of bending moment of pile body,and the maximum bending moment of structure.Through the data obtained from the experiment,the working mechanism of the shear bond supporting system is explained to a certain extent.In order to provide more theoretical basis for future research,the paper also uses Midas GTS NX software to analyze the whole test process by finite element simulation.A more comprehensive exploration of the whole supporting effect is carried out.We can also explore the uplift and settlement law on top and bottom of supporting pit.It not only perfects the research of the model,but also validates and supplements the results of the experiment.The results of the test and finite element calculation show that under the same excavation conditions,the displacement of the new shear bond support system is smaller.The maximum bending moment of the pile is smaller.And the uplift value and the settlement value are less than the cantilever pile system.It means that the shear bond system has a greater support depth.In practical engineering,the design requirements can be met with smaller pile diameter and reinforcement,which is more safe and cost saving.At the end of this paper,the research work is summarized,and the future research direction is prospected.更多还原