Mechanical Characteristics Of Bridge Piles Adjacent To Large Area Surcharge Load

Sometimes the foundation pile foundation not only bears the active load acting on the pile top directly,but also bears the lateral displacement caused by dead weight or external load of soil.Especially in the soft soil distribution area,the side displacement caused by the landfill loading is particularly obvious.If not handled properly,it will inevitably lead to serious engineering problems.However,the current analysis of such problems at home and abroad mostly relies on the estimation of engineering experience and lacks practical and effective analysis methods.Therefore,it is necessary to conduct a systematic study on the properties of such passive piles.The thesis takes the bridge pile foundation under the adjacent heap load as the research object.First,using the finite element numerical simulation method,the research on the working characteristics of the bridge pile foundation under the adjacent pile load was carried out,and the mechanism of the passive pile-pile-soil interaction was revealed.Then,based on the slip line theory and the plastic deformation theory,respectively,the interaction model between the displacement soil and the single pile and row of piles is constructed,which provides theoretical support for the determination of the passive load of the pile under the pile load.And on this basis,the differential equation of passive pile body response is derived and established,and the corresponding semi-analytical solution is given.Finally,the theoretical calculation method is verified and analyzed according to the actual project.The main tasks include:(1)Under the adjacent pile load,the upper part of the pile is pushed by the displacement and the soil shows the characteristics of the passively loaded pile,and the lower part is subjected to the resistance of the relatively stable soil to show the characteristics of the actively loaded pile.The soil displacement caused by the pile load will be blocked by the pile,which will form a soil arching effect,which will affect the force response of the pile.(2)Based on the slip line theory,construct a displacement soil-single pile plane strain interaction model.Considering the influence of the local development of the soil plastic zone around the pile on the passive load of the pile,the calculation method of the corresponding passive load of the pile is given.(3)Based on the theory of plasticity,construct a load transfer model of displacement soil-row piles.Considering the influence of the soil arching effect in front of the pile on the passive load of the row of piles,the corresponding calculation method for the passive load of the pile is given.(4)In view of the characteristics of the pile foundation of the adjacent pile-loaded bridge,the differential control equation of the passive pile force response considering the influence of the superstructure load is derived and established,and the corresponding semi-analytical solution is given.