潮汐区淤泥质地层CFG单桩施工力学特征研究

Study on Mechanical Characteristics of CFG Single Pile Construction in Muddy Soil in Tidal Area

摘要: 潮汐区淤泥质地层具有含水率大、抗剪强度低、孔隙比大、压缩性高等工程特征，采用CFG桩作为基础型式进行路基建设，在潮汐动水压力作用下CFG桩体完整性和承载能力会受到影响甚至改变。为探究潮汐区淤泥质地层CFG桩施工力学机理与动水圧影响效应，依托福鼎市滨海大道二期道路工程，基于大型有限元程序ABAQUS，建立潮汐区淤泥质地层CFG单桩三维施工力学计算模型，通过考虑振动沉管法CFG桩施工的拔管速度和潮汐孔压作用，研究CFG单桩施工过程中的竖向与水平变形特征，探究潮汐作用对CFG桩整体质量的影响规律。主要研究成果：1) 振动沉管法CFG桩施工的拔管速度对于CFG桩整体成桩质量有显著影响；2) 淤泥质地层在潮汐动水圧力作用下易侵入CFG桩体内，造成断桩等病害。

Abstract: The muddy stratum in tidal area has the engineering characteristics of high water content, low shear strength, large void ratio and high compressibility. The integrity and bearing capacity of CFG pile will be affected or even changed when CFG pile is used as the foundation for Subgrade Construction under tidal hydrodynamic pressure. In order to explore the mechanical mechanism and dynamic water pressure effect of CFG pile construction in tidal area, based on the second phase road project of Binhai Avenue in Fuding City and large finite element program ABAQUS, a three- dimensional construction mechanical calculation model of CFG single pile in tidal area is established. By considering the pipe pulling speed and tidal pore pressure effect of CFG pile construction with vibration sinking method, the construction process of CFG single pile is studied. Based on the characteristics of vertical and horizontal deformation, the influence of tide on the overall quality of CFG pile is explored. The main research results are as follows: 1) The speed of pulling out the pipe has a significant impact on the overall quality of CFG pile; 2) The muddy stratum is easy to invade into the CFG pile body under the tidal hydrodynamic pressure, resulting in pile breaking and other diseases.