【作者】 杨立功；

【导师】 王成华；

【作者基本信息】 天津大学 ， 结构工程， 2009， 硕士

【摘要】 由于诸多因素的影响,钻孔灌注桩的承载性状是很复杂的。钻孔灌注桩的施工过程是影响其承载性状的因素之一,若不考虑这个因素,理论上的桩的承载性状会与桩的实际承载性状有差距。因此,对考虑施工过程影响的钻孔灌注桩的承载性状的研究是必要的。本文在分析钻孔灌注桩施工过程的基础上,对钻孔灌注桩的施工过程做了一些简化与假定,应用大型非线性有限元分析软件ABAQUS模拟钻孔灌注桩的施工过程,并分析了施工过程中桩周土体应力变化以及施工过程对不同工况的钻孔灌注桩的竖向承载性状的影响。整个模拟过程由多个阶段组成,包括初始地应力平衡、桩位分段钻孔、泥浆护壁、混凝土分段浇注、混凝土硬化成桩、分级施加荷载、不同工况的钻孔灌注桩的竖向承载性状对比等。通过模拟分析,得到考虑施工过程影响的钻孔灌注桩的竖向承载性状。通过不同工况的钻孔灌注桩的竖向承载性状的对比,证明了不管是什么样工况的钻孔灌注桩,存在于桩侧土内的水平地应力的大小对桩的竖向承载性状有着显著的影响,桩的竖向承载力都随这个水平地应力的增大而增大。而且,当桩侧土体内的水平应力一定,径逐渐变小、土的静止侧压力系数逐渐变大时,桩的承载力、侧摩阻力、轴力都会逐渐增大;当桩长逐渐变长时,桩的承载力也会逐渐增大。更多还原

【Abstract】 Because of the influence of many factors, the bearing behavior of drilled piles is very complex. The construction process is one of the factors that influence the bearing behavior of drilled piles. If this factor is not considered, the difference between the theoretic bearing behavior of drilled piles and the actual bearing behavior of drilled piles is greater than that considers this factor. So, it’s necessary to research the bearing behavior of drilled piles considering construction process.On the basis of construction property of drilled piles, the construction process was assumed to be a simplified process, and the large nonlinear finite element ABAQUS program was used to simulate the construction process of drilled piles.Then, the change of the stress around the piles and the influence of construction process on different vertical bearing behavior of drilled piles were analysed.The simulating process comprised many different working conditions, including initial stresses, subsection bore, shaft wall protection by drilling mud, pile sbusection concreting, concrete pile harding, imposing grading load and the comparison of vertical bearing behavior under different working conditions.After simulation and analysis, vertical bearing behavior of drilled piles considering construction process was obtained. By comparing the influence of the construction process on different piles of working conditions, it proved that no matter what drilled piles of working conditions they are, the horizontal stresses existing in soil around pile obviously affected the vertical bearing behavior of drilled piles, and the vertical bearing capacity of the pile was improvd with the horizontal stresses; when the horizontal stresses existing in soil around pilewad fixed and the pile diameter becomed smaller and smaller and static lateral pressure coefficient becomed greater and greater, the vertical bearing capacity, the side friction and the axial force of the pile becomed greater and greater; when the pile length becomed longer and longer, the vertical bearing capacity of the pile also becomed greater and greater.更多还原