考虑桩土界面摩阻力的CFG桩复合地基沉降计算方法

The Settlement Calculation Method of CFG Composite Foundation Considering the Pile-soil Interface Friction

未考虑桩土界面摩阻力的CFG桩复合地基沉降计算值与实测误差不小,荷载传递法、桩间土竖向位移模式等方法虽然能考虑该摩阻力,却无法体现上部荷载对摩阻力的影响.为此,基于Berrum公式计算桩侧摩阻力假定,考虑了上部荷载引起的桩间土附加应力沿深度的变化和桩间土粘聚力对桩侧摩阻力的影响,推导了CFG桩复合地基的加固区沉降计算公式,以现场测试与模型试验共同验证了公式的合理性与准确度.

The relative error between the measured settlement data and calculated settlement value of CFG pile composite foundation without the pile-soil interface friction is significant and cannot be ignored.The supposed load transfer method and pile-soil vertical displacement pattern cannot reflect the effect of the load value on the pile shaft skin friction,though they can consider the pile-soil interface friction.As a result,based on the Berrum formula presupposition,this paper takes the additional stress change along the depth and the effective cohesion into account,derives the settlement calculation formula of reinforced zone in CFG pile composite ground,and makes proof of rationality and accuracy of the derived formula by means of site test and model test.