竖向受荷PCC桩宏细观工作性状研究

发布时间：2018-06-28 03:12

本文选题：桩基工程 + 模型试验　；参考：《岩石力学与工程学报》2015年07期

【摘要】：采用可视化模型试验及离散元数值仿真方法,对竖向受荷现浇混凝土大直径薄壁管桩(简称PCC桩)桩土传力特性、位移场发展规律及破坏性状进行深入研究。研究结果表明:PCC桩荷载沉降曲线呈缓变型,桩外侧摩阻力高于内侧摩阻力,内侧摩阻力发展滞后于外侧摩阻力,桩外侧摩阻力在桩身上段发挥较充分,内侧摩阻力在桩身下段发挥较充分,桩内侧摩阻力及端阻力控制PCC桩后期承载力;桩外侧土体以斜向下的剪切变形为主,其影响范围约为2D(D为外径);内侧以竖向压缩变形为主,加载初期与桩同步变形,加载后期桩内侧下部土体与桩之间相对位移明显大于桩内侧上部土体;桩端土体可分为圆锥形竖向压缩区及侧向变形区,其在深度方向的影响范围达到4D,桩端土变形模式在平面上呈扇形;接触力链的分布与侧阻力沿桩长分布特征基本保持一致,而桩端土孔隙率的变化则从细观角度反映侧阻先于端阻发挥。研究成果对于进一步明确PCC桩与土相互作用的内在机制具有意义。
[Abstract]:By means of visual model test and discrete element numerical simulation, the characteristics of soil force transfer, displacement field development and failure behavior of large diameter thin-walled tubular pile (PCC pile) under vertical loading are studied. The results show that the load-settlement curve of the pile shows a slow variation, the lateral friction of the pile is higher than that of the inner friction, the development of the inner friction lags behind the outside friction, and the lateral friction of the pile plays a more important role in the pile body. The inner frictional resistance plays a more important role in the lower part of the pile. The inside friction and the end resistance control the later bearing capacity of PCC pile. The lateral soil of the pile is mainly shearing deformation of oblique downward direction, and its influence range is about 2D (D as the outer diameter), and the inner side is dominated by vertical compression deformation. In the early stage of loading, the relative displacement between the lower part of the pile and the upper part of the pile is obviously larger than that of the upper part of the pile, and the soil at the end of the pile can be divided into conical vertical compression zone and lateral deformation zone. Its influence range in depth direction is 4D, the deformation mode of pile end soil is sector shape in plane, the distribution of contact force chain is basically consistent with the distribution characteristics of lateral resistance along pile length. The change of soil porosity at the end of the pile reflects that the lateral resistance is prior to the end resistance from a meso point of view. The research results are significant to further clarify the internal mechanism of interaction between PCC pile and soil.
【作者单位】：淮阴工学院建筑工程学院;江苏省建筑科学研究院有限公司;南京工业大学交通学院;
【基金】：国家自然科学基金资助项目(51408254) 江苏省自然科学基金青年基金项目(BK20130419)
【分类号】：TU473.1

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