刚性桩复合地基承载特性的试验研究

通过现场试验,测出了CFG桩不同深度处的桩身轴力和侧摩阻力,并得到了桩土应力比。分析了CFG桩复合地基中桩身轴力、桩侧摩阻力的分布及发展过程。研究了加载过程中桩侧摩阻力和端阻力荷载分担以及荷载分担比随外荷载的变化规律。最后介绍了CFG桩复合地基中负摩擦阻力的作用,得出了CFG桩由于褥垫层的设置,在加载初期,桩身存在负摩擦力,同时协调了桩土变形,使得桩土共同承担荷载,充分发挥土体的承载能力。

Study on Load-bearing Mechanism of Composite Foundation with Rigid Piles

Based on the field test,the axial force and side friction at different deepness levels as well as the pile-soil stress ratio had been measured,obtaining the distribution rules of axial force,side friction and entire process of load transmission.On this basis,the varying rules of the load-shared ratio of side friction and end resistance with the load increase were analyzed.At last,the role of negative friction in composition foundation with CFG piles was introduced.The results show that the negative friction exists in early loading because of the cushion;at the meantime,deformation between pile and soil is coordinated and pile as well as soil bears the load at the same time,which results in the increase of soil bearing capacity.