Numerical Analysis Of Uplift Bearing Capacity Behavior Of Rock-socketed Piles And Belled Piles

With the rapid development of municipal engineering,in order to alleviate the space constraints of urban development,lots of underground structures are built.The study on stability of underground structures resisting the uplift load is being adverted.And tension piles are usually used to resist the uplift load in the engineering practice.Meanwhile,tension piles are also widely employed to restrain a variety of land structures such as free standing and guyed lattice towers,television and transmission towers,tension cables for suspension bridges and tent-type roof and marine structures such as floating platforms,tension leg platforms and guyed towers.Although tension piles are widely used in the engineering,theories about tension piles are far behind of engineering practice.In this dissertation,the studies are emphasized on numerical analysis of uplift bearing capacity behavior of rock-socketed piles and belled piles under the vertical load and inclined load.The main investigations consist of the following parts:1.Base on finite element software ABAQUS,the finite element computational model for rock-socketed piles under vertical uplift load is established.On the basis of element finite results,the load transfer behavior is analyzed.Moreover,by parametric computation and comparative analysis,the ultimate uplift bearing capacity of rock-socketed piles under vertical uplift load is evaluated for different socket length,aspect radio of piles,elastic modulus of pile, elastic modulus of rock,elastic modulus of soil and horizontal load.2.Base on finite element software ABAQUS,the finite element computational model for belled piles under vertical uplift load is established.On the basis of element finite results,the load transfer behavior,displacement distribution of soil,equal plastic strain distribution of soil, and vertical stress distribution of soil are analyzed.Moreover,by parametric computation and comparative analysis,the uplift bearing capacity of belled piles and equal plastic strain distribution of soil are evaluated for different lengths,diameters,enlarged base depth,pile base diameters,elastic modulus of pile,elastic modulus of soil around pile segment,elastic modulus of soil around enlarged base,cohesion,angle of internal friction and friction coefficient.3.Utilizing user subroutines USDFLE and utility routines GETVRM to improve cohesive inhomogeneity.Based on this kind of foundation soil,the computational model for belled piles under the inclined load is established.On the basis of element finite results,relationship between inclined load and displacement,displacement and equal plastic strain distribution of soil under different direction of load are analyzed.At last,by parametric computation and comparative analysis,the inclined uplift bearing capacity of belled piles are evaluated for different elastic modulus of soil,angle of internal friction and cohesive inhomogeneity.