| If there is large-area fill, riprap stone or stacking fill nearby, negative friction will occur on the pile which is driven into compressible soil. Negative friction usually is dangerous to the pile and the building set on the pile. Negative friction is always the top important problem in geological engineering, In order to calculate and study the negative friction, displacement coordinated method is improved and the relative displacement between the pile and soil is considered. The consolidated quick direct shear test of the interface between soil and structural material is carried on and the load transfer function is presented. The consolidated quick direct shear tests of typical shanghai deposit and steel/concrete is carried on. Undisturbed and reconsolidated soil test are compared to research the difference. The relationship between the shear stress and shear displacemen is hyperbolic function. And the parameters of the load transfer function is presented. Using the displacement coordinated method, negative friction of pile under large-area stacking fill is calculated and analysed, and two effecting factor are discussed, In situ-test of a dock pile is carried on. The generation and development of negative friction is researched. Some methods of reduceing and preventing negative friction are presented. |
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