【作者】 王洋；

【导师】 张仪萍；

【作者基本信息】 浙江大学 ， 市政工程， 2010， 硕士

【摘要】 土工袋装桩型复合地基是一种新型的复合地基类型,不仅具有竖向增强体复合地基的典型特征,同时具有排水固结的加固效应,而且适合在非常软弱的土体中应用,有望成为一种更有效的软土地基处理技术,具有广阔的应用前景。本文以土工袋装桩型复合地基为研究对象,运用空间轴对称问题的相关理论,建立了土工袋装桩型复合地基应力应变分析和固结计算的解析理论,为土工袋装桩型复合地基的设计计算提供了科学合理的方法,以促进该种复合地基的推广应用。本文针对土工袋装桩型复合地基主要做了如下的一些工作:首先,在等应变条件下,采用由桩体、土工袋及其加固的桩周土体所构成的空间轴对称单元体模型,基于桩、袋、土均为线弹性体、忽略桩土自重的影响以及桩与土工袋和土工袋与土体界面处满足位移协调等必要的少数假设条件,分别应用位移法和应力法,推导了土工袋装桩型复合地基桩体和土体的径向位移和竖向位移、桩体和土体的各向应力以及土工袋围压的解析表达式。其次,在得到土工袋装桩型复合地基变形解析解的基础上,建立了在瞬时加载和非瞬时加载两种工况下土工袋装桩型复合地基固结问题的控制方程,并运用求解偏微分方程的相关方法,求得了控制方程的解答,进而得到了土工袋装桩型复合地基固结度的解析解答。最后,在所得到的关于土工袋装桩型复合地基变形和固结问题的解析解的基础上,分析了土工袋刚度、面积置换率、桩土模量比等参数对于其变形和固结的影响,对土工袋装桩型复合地基的工作性状做了较为详细的分析。本文所建立的关于土工袋装桩型复合地基变形和固结问题的解析理论,摒弃了传统理论中诸多的假设条件,是更完善的计算理论。严谨的解析理论有利于保障土工袋装桩型复合地基加固机理分析的科学性,研究成果为土工袋装桩型复合地基中的土工袋受力分析、固结性状分析等提供了合理的设计计算方法。更多还原

【Abstract】 Geosynthetic-encased column (GEC) is one kind of new composite foundation type not only has typical composite foundation characteristic of the vertical enhanced body, simultaneously has the drained consolidation reinforcement effect. So it can become one more economical effective soft clay ground treatment method hopefully. In this paper, we receive GEC as the object of study, use the correlation theories of the space axial symmetry and establish the stress-strain analysis and the consolidation analytical theory of GEC. The result of this paper provides the scientific and reasonable method for the design calculation of GEC, and promotes this kind of composite foundation to be popularization and application. All the work done is as follows:Firstly, under the equal strain condition, based on all the materials are linear-elastic homogenous materials, the column-soil system on a smooth base and neglecting the weights of column and soils, we use spatial axial symmetry unit cell model which constituted by the column, geotextile and surrounding soils. Then using the deformation method and stress method, we receive the analytical elastic solution expression of the radial and vertical displacements and all stresses of the column and the soil, as well as that of hoop force of the geotextile encasement.Secondly, on the basis of the analytical solution for deformation, we establish the consolidation governing equations of the GEC in two kinds of operating conditions of instantaneous load and non-instantaneous load. Then applying the relevant methods of partial differential equations, we get the solutions of consolidation governing equations. So the analytical solutions of consolidation degree for the GEC are obtained.Finally, we detailedly analysis the working properties of the GEC by discussing the influence of the stiffness of geotextile, area replacement ratio, modulus ratio and other parameters on the deformation and consolidation problems of the GEC.The analytical theory of deformation and consolidation problems about GEC establishing in this paper is the more perfect more scientific. This paper banishes many hypothesis conditions which were used by the traditional theories; the rigorous analytical solution theory is advantageous to safeguard the scientific nature of reinforcement mechanism analysis of geotextile coated column-type composite foundation, the research results can provide reliable and reasonable design calculation method for hoop force and consolidation property of GEC.更多还原