【作者】 刘永超；

【导师】 郑刚；

【作者基本信息】 天津大学 ， 岩土工程， 2009， 博士

【摘要】 预应力混凝土管桩具有桩身强度高、施工速度快、质量易保证、节能环保等优点,近年来在我国城乡建筑各领域得到了广泛的应用,已成为天津市大量使用的桩型。本文总结了国内外有关预应力混凝土管桩的研究现状和发展趋势,针对预应力混凝土管桩的抗剪强度、抗拔桩受力性能及注浆提高承载力等关键性问题,主要进行了以下几方面的工作:为研究预应力混凝土管桩的箍筋配筋率、剪跨比、混凝土强度、有效预压应力和以及主筋配筋率等对预应力混凝土管桩抗剪承载力的影响,进行了专项抗弯和抗剪承载力试验,综合分析了试验结果,结合管桩结构受力理论,提出了不同条件下的管桩抗剪承载力的计算方法,为管桩受水平力荷载下的基础设计提供了依据,并为管桩抗震验算提供参考。通过对预应力混凝土管桩桩身、焊接接口、与承台连接强度和抗拔静载性能等专项试验,研究了预应力混凝土管桩的受拉承载性能,量化分析了将其作为抗拔结构时的端板、墩头、焊缝及桩身的抗拔性能及破坏形式,通过理论分析提出了管桩用作抗拔桩设计的基本原则和抗拔管桩的控制节点。本论文开发出一种适用于软土地区的扩孔灌浆管桩,将灌注桩中的后注浆工艺和采空区灌浆工艺引入管桩工程中,将管桩端部通过扩大钢板挤扩出孔隙以方便灌浆和注浆,使桩周土、灌浆注浆体与管桩密切结合,形成高抗压承载力、高抗拔承载力、高水平承载力以及利于抗震性能提高的新工法。对扩孔灌浆管桩的桩土共同作用机理进行系统研究,针对不同的受力特性选择了适宜的浆液配比、注浆压力控制标准和注浆量,研究了管桩经注浆后承载力提高的工作机理。通过对现场测试和理论分析相结合的系统研究,可以促进管桩的科研开发、设计、技术服务等各方面工作,取得了很好的经济社会效益,也为本项目研究成果的实施和技术推广奠定了基础。更多还原

【Abstract】 Prestressed concrete pipe pile has several advantages, such as, high strength of pile body, high construction speed, easy quality assurance, energy saving, environmental protection and so on, so it has been used widely in many fields of urban and rural construction in our country, and what’s more, it has been a large-scale used pile type in Tianjin. The research status quo and development trends of the prestressed concrete pipe pile at home and abroad are summarized in this paper. In order to solve some key problems, for instance, shear strength of prestressed concrete pipe pile, behavior of uplift pile under force, grouting to improve bearing capacity and so on, the following aspects of work have been done.In order to research the influence of stirrup reinforcement ratio, shear span ratio, concrete strength, effective prestress and reinforcement ratio of prestressed concrete pipe pile on its shear strength, special experiments of flexural bearing capacity and shear capacity have been carried out. Based on the analysis of experiment results and the structural theory of pipe pile under force, shear capacity calculation methods of pipe pile under different conditions are raised. This provides the basis for the design of pipe pile under horizontal force, and this can also supply references to seismic checking of pipe pile.Through special experiments of pile body, welding interface, joint strength to platform on piles and performance under static tension, the tensile bearing capacity of prestressed concrete pipe pile has been researched, and uplift bearing capacity and destructional forms of two ends, weld joint and pile body of prestressed concrete pipe pile as tensile structure have been quantitatively analyzed. Through theory analysis, it has been raised that the basic design principle of pipe pile as uplift pile and control node of uplift pipe pile.A kind of reamed grouting pipe pile that is suitable for soft soil area has been developed. Post grouting technology of bored concrete pile and grouting technology of mining area are introduced to pipe pile engineer. Using extended steel plate at the end of pile to ream pores makes grouting easily, and grouting makes the soil around pile, grout and pipe pile connected closely, so that compressive bearing capacity, tensile bearing capacity, lateral bearing capacity and aseismatic performance are all increased. Soil-pile interaction mechanism of reamed grouting pipe pile has been researched systematically, and for different bearing characteristics, appropriate grout ratio, grout pressure control standard and grout quantity are determined. Working mechanism of the increase of bearing capacity of pipe pile after grouting has also been researched. Systematic research that combines field testing with theory analysis can promote many aspects of work of pipe pile, like research development, design, technical service and so on. This research can make very good economic and social benefits, and it can also lay the foundation for the implementation of achievements of this project and technique extension.更多还原