The Experimental And Numerical Analysis Of Pile Foundations Behavior Under Inclined Loadings

Pile foundations, such as those used in ports, bridge and offshore platforms and so on, are mainly subjected inclined loadings, not only vertical or horizontal loadings. The inclined loadings are usually divided into vertical and horizontal loadings when the mechanism and properties of piles under inclined loadings are investigated. Then, the pile response is studied under individual loading and the inner force and displacement can be calculated according to the superposition principle of small deformation. The cross section moment is modified by multiplying a modified coefficient when checking the cross section strength. At present, little research work has been done on the mechanism and behavior of vertical pile under inclined loadings.In order to further investigate the behavior of piles under inclined loadings, the experimental model tests has been done to reveal the loading ability and loading transfer mechanism of single vertical bearing piles under horizontal loading, horizontal bearing piles under vertical loading and vertical piles under inclined loading. Then, the behaviors of single piles and pile groups under inclined loadings are analyzed using numerical simulation. The main c??nt of this paper can be summarized as follows:(1) A brief introduction on the history of development in pile foundations, and the research status and results at home and abroad of piles under vertical loading, lateral loading or coupled vertical-lateral loading are discussed.(2) Some laboratory model tests are made of piles under inclined loadings. With the aid of experimental study of model piles, it is revealed the effects of lateral loading on the settlement and moment of vertical-bearing piles, the effects of vertical loading on the horizontal displacement and moment of horizontal-bearing piles and the effect of horizontal loading on the settlement of piles by increasing horizontal and vertical loadings under same loading ratio.(3) The behavior of inclined-loading pile is numerically simulated and analyzed using finite element analysis software ABAQUS 6.5. In the analysis, the soil nonlinear is simulated using elastic and modified Cam-clay models, respectively. The contact elements around the pile-soil interface are set to represent the slippage and separation of pile-soil system. By means of different calculation model and different loading combinations, the effects are investigated of lateral loading on the vertical-bearing pile's settlement, of vertical loading and eccentric vertical loading on the lateral-bearing pile's lateral displacement and of inclined loading with different inclination angle on the vertical pile's settlement, lateral displacement and flexibility.(4) The effects are further analyzed of lateral loading on the settlement of vertical-bearing piles, vertical loading on the flexibility of horizontal-bearing piles and inclined loading with different inclination angle on the pile's flexibility and moment. The numerical results obtained are compared and analyzed with the field testing results, which indicates that they agree very well.(5) The internal ??e, displacement and moment of group piles are studied under different loading magnitude and inclination angle using numerical simulation and analysis. Based on the results obtained, it is found that the magnitude and inclination angle of loading have a great influence on the pile's moment, and the existing of side piles can reduce the friction of middle piles. On account of group piles effects, side piles have a role of impede on the middle piles, which can further reduce the middle pile's moment at a certain extent.