Simulation Study On Pile Group Effect Of Pipe Pile Foundation Under Vertical Load

In recent years,with the rapid development of the national economy,a large number of buildings emerge in an endless stream.Therefore,in order to ensure the safety and stability of buildings,the stability of the foundation must be taken into account in the first place.Because of the high bearing capacity and fast construction speed,pile foundation is more and more widely used in the field of construction engineering.However,because pile group foundation can not carry out a large number of field tests,and the scale test is difficult to fully reflect the actual working state of pile group,so using finite element simulation to study pile group has become a new method.Based on a pile foundation project in Handan City,the pile group effect in this area is studied.Firstly,the research status of pile foundation is briefly summarized,the working mechanism of single pile and pile group is analyzed,and then the principle of finite element method is introduced.Then,the finite element software ABAQUS is used to simulate the single pile and pile group respectively.The simulated settlement,single pile load test and building settlement are compared,and the software parameters are adjusted continuously to obtain more reliable software parameters.On this basis,finite element simulation is carried out for different spacing and length of piles.Under different pile spacing,when the pile spacing is 3 D,the non-uniform settlement of central pile,side pile and corner pile is the largest.With the increase of pile spacing,the non-uniform settlement decreases gradually.In terms of final settlement,the increment of pile group settlement gradually decreases with the change of pile spacing from 3D to 6D.When the pile spacing is 4D,the side friction is the largest,the smallest at 5D,followed by 3D and 6D.The maximum value of side friction is found at the distance of 4m~6m from the end of the pile.When the pile spacing is 4D,the maximum end resistance appears in the central pile position,and the end resistance of side pile and corner pile is similar.When the spacing between piles is 5D and 6D,the resistance at the end of each pile has no difference.Under different pile lengths,when pile lengths increase from 10 m to 15 m,settlement decreases by about 50%,while when pile lengths increase from 15 m to 20 m,settlement decreases by only 33%.Along the direction of the pile body and with the increase of the length of the pile,the exertion of the lateral resistance is getting higher and higher.When the pile length is 10 m,the resistance at the end of the pile is the largest,and the difference between the resistance at the end of the pile is small when the pile length is 15 m and 20 m.This shows that under this soil condition,when the pile length is 15 m,the exertion of the resistance at the end of the pile is not affected by the different pile length.