The Study On The Compression And Stability Of The Super Long Pile In The Soft Soil

First of all, the characteristics of concrete, reinforcing bar and super-long pile are presented. And then it put forth that it is unreasonable to use the concrete elastic modulus to simulate the response of the pile embedded into soils because of the difference between the elastic modulus of concrete and the deformation modulus of pile shaft. This difference is mainly due to that the responses of concrete subjected to uniaxial stress and tri axial stress are different.In the next part, a new method is developed to calculate the deformation modulus of pile shaft. In this model, the influence of the reinforcement ratio on the deformation modulus of pile shaft is taken into account, and based on the whole stress-strain curves, the values of the deformation modulus of pile shaft are obtained considering the strengthen influence of the reinforcement hooped spiral. Furthermore, the formula of the elastic compression of pile is derived considering the effect of the reinforcement.The stability of the super-long pile embedded into soft soils should be considered. Herein the assumptions of the triangular distribution and uniform distributed are adopted to simulate the pile side resistance, and M-method is used to simulate the soil counterforce. And then the critical load is given using the Galerkin method.Form the data of 1800 piles, it can be concluded that the compression of pile shaft increases with increasing pile length and loading level, and the increased trend is not significant when the pile length and pile head load are larger than a certain value. The error between the measured and the calculated value of the compression of pileshaft increases with increasing pile length. Moreover, a statistical coefficientΨ=ξ_eE_c/E_s, isused to present the pile compression coefficient and the error between the elastic modulus of concrete and the deformation modulus of pile shaft. In addition, a linear regression formula is given. In the last of this paper, the rationality of the proposed method is proven using an engineering example, and some suggestions for the engineering practice are put forward.