桩筏基础的优化设计与研究

发布时间：2018-01-11 17:14

本文关键词：桩筏基础的优化设计与研究　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：桩筏基础由于在控制沉降差方面有着独特的优点,现已成为一般高层建筑中最常用的基础型式。但在实践中,由于缺乏桩和桩间土之间相互作用的合理计算公式,中国房屋建筑进行桩筏基础设计时,计算仍采用简化算法,降低了桩间土对地基承载力的提高作用,相应地增加了桩的数量和长度,导致基础承载力有较大的富余量,从而造成一定的经济建设浪费,但由于高层建筑桩筏基础是一个十分复杂的系统,它们共同作用的研究关联到很多因素,基于此,对其工作机理的深入研究是非常有必要的。本文对现阶段国内外桩筏基础的研究成果进行了总结,在对桩筏基础的工作原理理解的基础上,采用PKPM建立模型,模拟计算了多种工况下桩筏基础的沉降情况。关于桩筏基础的优化设计,本文主要是从控制沉降方面来进行了理论和计算分析。主要内容有:以一个实际工程为研究对象,用PKPM软件中JCCAD模块为计算工具,计算了桩筏基础在不同布桩的条件下的沉降情况,并根据PKPM计算出的单桩最大反力值,以及筏板的实际沉降、筏板的配筋量这些方面,进行了对比分析;然后用FLAC3D模拟了桩在实际土层中的受力情况,根据计算结果,可以在设计时适当提高地勘所提供的单桩承载力特征值;最后依据理论、试验和数值分析的结果提出了改善桩筏基础工作效率的优化设计方法,即调整布桩方式。其中调整布桩方式主要包括改变桩长、改变桩距、改变桩径等等,并提出了根据上部荷载布置桩,并改变桩长的一般布桩原则。综上所述,本论文主要研究了高层建筑桩筏基础的工作性状进,结合数值分析以及模型试验得到最终的结论,同时提出变刚度调平设计的指导思想与原理,提炼出一套优化桩筏基础设计的方法,这对工程实用具有重要的借鉴意义。
[Abstract]:Because of its unique advantages in controlling settlement difference, pile-raft foundation has become the most commonly used foundation in general high-rise buildings, but in practice. Due to the lack of a reasonable formula for calculating the interaction between piles and soil between piles, the simplified algorithm is still used in the design of pile-raft foundation in Chinese housing buildings, which reduces the effect of increasing the bearing capacity of soil between piles on the foundation. The corresponding increase in the number and length of piles, resulting in a large surplus of foundation bearing capacity, resulting in a certain amount of economic waste, but because of high-rise building pile-raft foundation is a very complex system. The research of their interaction is related to many factors, based on which, it is very necessary to study the working mechanism. This paper summarizes the research results of pile-raft foundation at home and abroad at present. On the basis of understanding the working principle of pile-raft foundation, the model of pile-raft foundation is established by using PKPM, and the settlement of pile-raft foundation under various working conditions is simulated and calculated. The optimum design of pile-raft foundation is discussed. This paper mainly carries on the theory and the calculation analysis from the aspect of controlling the settlement. The main contents are as follows: take a practical project as the research object, use the JCCAD module in the PKPM software as the calculation tool. The settlement of pile-raft foundation under different pile distribution conditions is calculated, and the maximum reaction force of single pile calculated by PKPM, the actual settlement of raft plate and the reinforcement of raft plate are compared and analyzed. Then FLAC3D is used to simulate the bearing capacity of the pile in the actual soil layer. According to the calculation results, the characteristic value of bearing capacity of single pile can be improved properly in the design. Finally, based on the results of theoretical, experimental and numerical analysis, an optimal design method is proposed to improve the working efficiency of pile-raft foundation, that is, to adjust the layout of piles, which mainly includes changing the length of piles and changing the spacing of piles. Change pile diameter and so on, and put forward the general principle of pile layout according to the upper load and change pile length. In summary, this paper mainly studies the working behavior of pile raft foundation of high-rise building. Combined with numerical analysis and model test, the final conclusion is obtained. At the same time, the guiding idea and principle of variable stiffness leveling design are put forward, and a set of optimization method of pile-raft foundation design is refined. This is of great significance to engineering practice.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU47

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