Based on the contrast of grouting and re-beating of floating piles,the latter should be adopted in soft soil foundation.

Aimed at the phenomena of floating pile in construction of 100000 m2 high building with prestressed concrete pipe piles,the influence of floating on shaft resistance,toe resistance and bearing capacity of pile were studied through the analysis of static load tests of engineering piles.

For possible floating piles in strengthening weak foundation of highway with cement mixing piles, the relationship be-tween total settlement of the foundation and thickness of underlying un-strengthened soil layer is derived on the basis of two models.

Dynamical stiffnesses of a floating pile in horizontal vibration;

Dynamic stiffness for lateral vibration of a viscoelastic floating pile in a nonlinear viscoelastic soil layer is investigated.

Following the theory of incompressible saturated viscoelastic porous media and one-dimensional bar model, the dynamical stiffness of a floating pile vertically vibrating in a viscoelastic saturated soil layer is investigated.

Based upon the results obtained from geological inspection, design, monitoring and construction, the upfloat of prestressed pipe pile is analysed.

Taking the low-strain dynamic testing curves of rotary drilling cast-in-place piles for the Shuiyang River Bridge as example,this paper analyzed the effects of pile head laitance and pile shaft belly on the low strain dynamic testing curves.