Numerical Analysis On Mechanical Behavior Of Single Pile In Clay Under Lateral Loads

With the countries' increasing requirement of new energy,development and utilization of marine resources has a significant meaning to investigate.Most sea buildings or marine structures are surporrted with pile foundation,which usually under lateral loads acting.Therefore,the mechanic behavior of pile planted in soil under lateral loading is of great importance to the design of marine structures.However,previous numerical and model test studies of pile under lateral load are limited to sandy soil and relatively less research concerning clay soil.Futhermore,pile foundations planted in the sea,rivers or slopes are large diameter,which are quite different from the applicable situation of the general API method.It would be meaningful to use the FEM method,which has been verified with the experimental test,to study the mechanical behavior of pile under lateral loads in clay soil and make a comparison with the API specification method.By using a FEM code DBLEAVES,this paper established three 3D finite element model and one 2D model studied the mechanic behavior of a single pile under lateral load in clay.The Drucker-Prager constitutive model and the cyclic mobility constitutive model(namely C-M method)is used in DBLEAVES.In this paper,the Drucker-Prager method is took the difference pile types and soil cohesion into account to learn its affect to the mechanical behavior of the lateral laoded pile;the connective between Drucker-Prager method and cyclic mobility method is build and the difference of Drucker-Prager method and cyclic mobility method for the result of lateral loaded pile is discussed;the cyclic mobility method is used to expore the 2D soil-pile interaction of the rigid pile under dynamic lateral load.The main research are as follows:(1)By comparing the pile load-deformation curve of the centrifuge tests and API specification method under lateral load in clay,this paper verified the calculation laod-displacement curves of the Drucker-Prager method that elastic modulus is constant in DBLEAVES.The verified Drucker-Prager method is used to consider the influence of joint,soil cohesion to laod-displacement curve.Also,the Drucker-Prager model which elastic modulus is line changed,is simulated well with the centrifuge test laod-displacement results of lateral loaded pile in clay.(2)By establishing the strength relationship of a single element between Drucker-Prager method and cyclic mobility method,this paper succeeded in appling the dynamic constitutive cyclic mobility model to calculate the laod-displacement curves of the lateral loaded 3D FEM pile in clay.(3)The cyclic mobility dynamic constitutive model is applied to 2D FEM of lateral loaded pile in clay.This article described the load-displacement curve of dynamic lateral load pile and studied the regulation of the stiffness change of the load-displacement curve.It also considered the effection of dynamic lateral load to the the lateral ultimate pile capacity.