桩土相互作用机理与力传递分析新方法以及新型线性桩的研究

发布时间：2018-09-19 13:07

【摘要】：伴随我国各项产业快速发展,桩基础得到了广泛的利用,是一种重要的基础形式。同时,随着社会经济的发展,作为所有国家中人口最多的中国,人口大量涌进城市,城市建设用地随着城市人口的集中而日益紧张。为缓解这个问题,其中一种办法是尽量建造多层甚至高层建筑。而该办法会使我们对地基及基础有更高的要求,尤其是沿海地区。由于稳定性高、承载能力强、沉降小且均匀,桩基础成为所有基础设施的首先形式,但桩基础存在一个问题,它的造价相对较高,能占总价的1/4甚至还要高。所以使得各个单位研究如何减小造价,因此桩基的理论、设计及施工方法得到了发展。近些年来这方面的研究虽取得一些成果,虽然近些年取得了一定的成果,但因为造成变形及受力因素较多,如桩的类别、排列方法、桩的尺寸、桩数和施工方式等,故很难研究桩的变形状态及受力情况。所以若相关理论不完善则会使设计出的产品不能用于实际。若选用的浅基础不满足强度和变形的要求,我们就可改用桩基础,由承台和桩共同组成一个系统,该系统可承受上部结构传来的荷载,产生群桩效应。桩基工程发挥了它的巨大作用,得到了广泛的应用,各种各样的桩型都应运而生,但是,至今未为,大多数用来描述桩土相互作用的力学模型,采用的都是理想的弹塑性模型。或者分段线性化的软化模型,这些模型难以描述连续软化的力学特征。在这种情况下,新发明提出了“桩土相互作用机理及力传递分析新方法”,该发明解决了桩土相互作用软化特性难以描述的难题,并指出了桩顶P-S关系曲线与岩土体力学特性的相互关系,从力学原理出发,指明了沿桩身可以划分为稳定区、欠稳定区、临界区和破坏后区的观点,提出了新发明模型参数的决定方法。并且,迄今为止,基桩大多数是等截面等强度设计,没有结合具体地质条件进行有针对性基桩设计,因而造成了巨大浪费;另外,如何设计最为安全、经济的合理桩型,迄今没有具体的相应理论支持(简称:基桩设计优化原理);新的发明主要针对上述两个方面提出了基桩设计原理、计算方法和优化原理。新发明提供了桩土作用的本构模型,并发明了该模型的参数决定法;对基桩计算提出了力法和位移法。桩身本构模型采用现行线性或弹塑性模型,采用新的发明提出的模型可以模拟在粘土区增加桩长桩顶承载力提高不大,优化基桩设计、确定桩身断裂位置等有利于设计及施工发展。
[Abstract]:With the rapid development of various industries in China, pile foundation is widely used and is an important foundation form. At the same time, with the development of social economy, as the largest population in all countries, China has a large number of people into the city, urban construction land with the concentration of urban population and increasingly tense. One way to alleviate this problem is to build multi-storey or even high-rise buildings as much as possible. This approach will result in higher demands on foundations and foundations, especially in coastal areas. Because of its high stability, strong bearing capacity, small and uniform settlement, pile foundation becomes the first form of all infrastructure facilities, but the pile foundation has a problem, its cost is relatively high, it can account for a quarter of the total price even higher. So every unit studies how to reduce the cost, so the theory, design and construction methods of pile foundation have been developed. Although some achievements have been made in this field in recent years, although some achievements have been made in recent years, there are many factors that cause deformation and stress, such as the category of piles, the arrangement method, the size of piles, the number of piles and the construction methods, etc. Therefore, it is difficult to study the deformation and stress of the pile. Therefore, if the relevant theory is not perfect, the design of the product can not be used in practice. If the shallow foundation is not satisfied with the requirements of strength and deformation, we can use the pile foundation, which is composed of cap and pile, to form a system, which can bear the load from the superstructure and produce pile group effect. Pile foundation engineering plays an important role and has been widely used. All kinds of pile types have come into being. However, most of the mechanical models used to describe pile-soil interaction are ideal elastoplastic models. Or piecewise linearized softening models, which can hardly describe the mechanical characteristics of continuous softening. In this case, the new invention "pile-soil interaction mechanism and force transfer analysis of a new method", the invention solved the pile-soil interaction softening characteristics difficult to describe the problem. The paper also points out the relationship between the P-S relation curve of the pile top and the physical properties of the rock and soil. Based on the mechanics principle, it points out that the pile body can be divided into the stable region, the understable zone, the critical zone and the post-failure zone. The method of determining the parameters of the new invention model is put forward. Moreover, up to now, the foundation pile is mostly iso-section and equal strength design, and has not combined with the specific geological condition to carry on the pertinence foundation pile design, thus has caused the huge waste; in addition, how to design the most safe, economical reasonable pile type, So far, there is no specific theoretical support (abbreviated as the optimization principle of foundation pile design), and the new invention mainly puts forward the design principle, calculation method and optimization principle of foundation pile in view of the above two aspects. The new invention provides the constitutive model of pile-soil interaction, and invents the parameter determination method of the model, and puts forward the force method and displacement method for pile calculation. The existing linear or elastoplastic model is used in the constitutive model of pile body, and the new model can be used to simulate that the bearing capacity of pile length pile top can be increased little in clay area, and the design of foundation pile can be optimized. Determining the fracture position of pile body is beneficial to the development of design and construction.
【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】：TU473.1

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