Analysis Of Ultimate Bearing Capacity Of Pile Foundation For Marine Floating Structures

As foundations for high buildings, pile foundations often bear vertical pressure loads. However, with the development of construction technologies for offshore engineering, submerged floating tunnels, anti-pulling pile foundations bearing inclined loads become an important type of foundation in deep water. Until now, the researches on anti-pulling piles are not enough comparing with the piles bearing pressure load, so it is necessary to study on the bearing capability of anti-pulling piles.The present situation of this research is introduced firstly. Based on the finite element method, a symmetrical 3-D model of single pile is established, in which Mohr-coulomb model and linear elastic model are used for soil and concrete materials respectively. Setting Contact elements on the interface of pile and soil for considering friction, the bearing capability of pile is simulated and the ultimate bearing capacity, displacement properties and the influencing factors are mainly analyzed.The specific contents are as follows:(1) By means of reading references, the research status of submerged floating tunnel, foundation types of marine floating structures, the basic theories of finite element method and elastic-plastic model of soil were introduced.(2) The simulation of the interaction between uplift pile and soil was presented by finite element method. By comparing the numerical results with experimental results by other researcher, the rationality of the model established was verified.(3) The ultimate bearing capacity, deformation characteristics and the influencing factors of the inclined uplift pile were investigated. Firstly, the differences of bearing capacity between uplift pile and compressive pile were studied. And then, effects of load inclination, pile length, pile diameter and soil parameters on the bearing capacity of the inclined uplift pile were considered respectively. The results show that, the bearing capacity of compressive pile is larger than that of the uplift pile; the transmission mechanism of friction between pile and soil are similar for both. The ultimate bearing capacity of inclined uplift pile improves gradually with the increase of the load inclination, pile length, pile diameter, pile modulus, soil cohesion and soil modulus.(4) Dynamic ultimate bearing capacity of inclined uplift pile under cyclic loading was studied. The influences of load cycle times, static stress ratio, pile length, pile diameter and pile modulus on the cyclic ultimate bearing capacity of inclined uplift pile were analyzed. Finally, it is compared with the static ultimate bearing capacity under same conditions.