Analysis Of Stress And Deformation Of The Tension Pile Considering Pile-soil Interface Shear Displacement Characteristic

With the urbanization of our country,the construction of underground structure shows the momentum of rapid development.In coastal areas,the underground structures tend to be more bouyant because of higher water levels.It has become the most widely used type of anti-floating foundation in the current application,which is characterized by low input,simple construction process and good performance.So far,there has been a lot of fruitful research by scholars in China and abroad.These studies mainly focus on the uplift pile ultimate bearing capacity,also on the study of the deformation mechanism of uplift pile is often based on the field test,and the lack of in-depth theoretical study.However,the displacement of the pile under load has a direct effect on the safety and stability of the whole structure.In engineering practice,it is not simple to use the bearing capacity as the design standard for the requirement of the deformation and displacement of the pile foundation.Therefore,it is of great practical significance to study the displacement relation of pile load.When the traditional analytical method is analyzed,the shear displacement characteristics of the pile-soil interface are not fully considered.In fact,it is widely recognized that the shear band with certain thickness would be generated on the pile-soil interface when the pile is subjected to external loads.The shear band is featured by the relative displacement between the pile body and the surrounding soils which would mobilize the skin friction on the pile surface.Reversely,the friction exerting on the surrounding soils can propagate away from the pile and render the soils experience elastic deformation.Hence,the displacement of pile at any position can be partitioned to the relative displacement on pile-soil interface and the displacement of surrounding soils.A novel load transfer function characterizing the relation of the skin friction and the relative displacement on pile-soil interface was established based on the conventional shear displacement model of pile-soil interface.By incorporating with the Mindlin solution and the shear displacement method in solid mechanics to solve the soil deformation induced by the propagating skin friction,the profile of displacement and uplift load at pile top for the tensile pile was obtained.For further research on load transfer mechanism of the uplift pile,this paper constructs the pile-soil interface hyperbolic model,the pile-soil interface three line model and the pile-soil interface elastic-plastic model and so on three load-transferring model for pile-soil interface,corresponds to the hardening,softening,and neither hardened nor softened of the soil.Analysis results show that,compared with the traditional model of piles and soil,the pile soil interface model can be more real reflect uplift pile load mechanism,the method calculated value than the traditional load transfer method corresponding calculation values closer to the measured values.Finally the finite element software ABAQUS is used to simulate the load bearing machnism of the pile,and the deformation chracteristics of the pile are discussed more in-depth.