软土地基中纺锤型桩负摩阻力特性研究与控制地面沉降技术应用

发布时间：2018-03-15 06:03

本文选题：纺锤型桩　切入点：有限元数值模拟　出处：《浙江海洋学院》2015年硕士论文　论文类型：学位论文

【摘要】：我国沿海地区分布有大量新沉积细颗粒土,多为淤泥质软土,其力学性质为孔隙比大,含水量高,常表现出欠固结性。这类沉积土用于农业设施基础时,由于地基软弱,常采用桩基础。欠固结土固结过程中会引起地基土沉降,产生桩侧负摩阻力,对桩产生下拽力,可能会造成桩身破坏、桩端地基的破坏等;地基一旦沉降幅度较大,就会使承台底部与地基土相互脱离,产生承台脱空现象;地基沉降可能也会对临近的建筑物产生影响,使临近建筑物产生倾斜或者裂缝,造成严重的工程事故。因此,我们需要对软土中桩身负摩擦力问题及地面沉降问题进行研究。本文提出了一种新的桩型-纺锤型桩,研究其桩侧负摩阻力特性和控制地面沉降的技术应用。首先根据桩的形状和受力情况,对纺锤型桩负摩阻力特性进行理论分析。其次,运用ABAQUS软件分别建立纺锤型桩与等截面单桩的三维有限元数值分析模型,通过数值模拟分析影响桩侧负摩阻力的几个主要因素,如摩擦系数、土的内摩擦角、粘聚力、桩顶载荷、地面堆载和土体固结时间等。对比纺锤型桩较等截面桩的优势,研究结果证明,纺锤型桩锥角的存在有利于减少桩负摩阻力,提高桩基承载力,减少地面沉降。最后,文章介绍了纺锤型桩的构造设计、工作原理以及桩土相互作用机理,表明其在控制地面沉降、防治承台脱空的优越性,从而指出纺锤型桩值得推广应用。新型纺锤型桩的研究将是一项具有创新性的研究工作,该桩型具有承载力高、型式简单、施工方便,恰当地运用该工艺可以节省材料,提高承载力,能有效地减少负摩阻力对基桩的影响,对于欠固结地基中农业设施的建造与使用具有重要的理论价值和工程意义;掌握地面沉降控制技术,能更好的减少工程隐患,保证人们的生命财产安全;因此,该研究具备较高的学术价值和工程应用价值。
[Abstract]:China's coastal area distribution of a large number of new deposits of fine soil, mostly silt soft soil, the mechanical properties for large void ratio, high water content, often exhibit less consolidation. This kind of sedimentary soil for agricultural infrastructure, because the foundation is weak, often uses the pile foundation under consolidated soil consolidation will be. Due to the sedimentation of foundation soil in the process of producing, pile side friction of pile, downdrag, may cause damage of pile, pile foundation settlement failure; once greatly, will make the bottom of cap and soil from each other, which may cap the void phenomenon; foundation settlement will also close the buildings affect nearby buildings tilted or cracks, causing serious engineering accident. Therefore, we need to carry out research on soft soil pile friction and the ground settlement problems. This paper presents a new type of pile - spindle type pile. Application of the pile side friction resistance and negative characteristics of ground subsidence control. According to the pile shape and stress, theoretical analysis of the spindle type of negative friction resistance of pile characteristics. Secondly, establish spindle type pile and single pile with uniform cross section of the three-dimensional finite element model using ABAQUS software, through the analysis of numerical simulation several main factors of negative friction resistance of pile side effects, such as friction coefficient, internal friction angle of soil, cohesion, load of pile top, ground loading and consolidation time. Compared with the uniform pile pile spindle advantages, research results show that the cone angle of the spindle type pile is conducive to reduce the negative friction of piles resistance, improve the bearing capacity of pile and reduce the surface subsidence. Finally, this paper introduces the structural design of spindle type pile, the working principle and the pile-soil interaction mechanism, demonstrate the superiority of prevention and control of ground settlement, pile cap removal from empty. And pointed out that the spindle type pile is worthy of popularization and application. Research on a new type of spindle type pile is an innovative research work, this type of pile has high bearing capacity, simple type, convenient construction, proper use of this technology can save materials, improve the bearing capacity, can effectively reduce the effect of negative friction on pile foundation that has important theoretical value and engineering significance to the construction and use of under consolidated soil agricultural facilities; control technology of ground subsidence, can better reduce the project risk, ensure the safety of people's life and property; therefore, the research has high academic value and engineering application value.

【学位授予单位】：浙江海洋学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU473.1;TU433

【参考文献】