On Horizontal Bearing Capacity Behavior Of Super-Long Piles In Layered Soil

With a rapidly increasing number of ultra-high-rise buildings,large-span bridges,large coastal ports and offshore platforms,super-long piles,compared with ordinary piles,are widely used in engineering construction with their advantages of strong bearing capacity and outstanding stability.In the existing researches on pile foundations,the researches pay more attention on the vertical bearing capacity of the pile foundations and less attention on lateral bearing capacity thereof.In large engineering projects,particularly offshore platforms,offshore wind turbines,large-span bridges and the like which would be affected by lateral wind power,earth pressure and waves require higher lateral bearing capacity.Besides,it's a rarity to see uniform soil layer in practical engineering.Therefore,when the analysis of horizontal load is carried out,it is also significant to fully consider the property differences of various soil layers.In view of this,this paper carries out a research on the lateral bearing capacity of super-long piles in layered soil.(1)Basic equations of multilayer elastic soil system under horizontal concentrated loading is obtained by introducing a layered elastic theory;and lateral displacement of double-layer elastic soil is obtained through numerical integration by means of Matlab;and the lateral displacement of double-layer elastic soil corresponding to the elastic module ratio between different shallow-layer soil thickness and soil layer is analyzed by using examples.This solution can well reflects the impacts of soil layering characteristics and soil stiffness..(2)A numerical simulation for horizontally loaded piles in double-layer soil is run by using finite elements software COMSOL;the correlation curve of pile top displacement and horizontal load is drawn by using test pile data and finite element simulation results to carry out an analysis;and thereby the correction of pile-soil system finite element analysis is verified.(3)A modified method for the horizontal displacement of super-long pile in double-layer soil is proposed;a numerical simulation for the pile-soil system is performed by using COMSOL;a fitted modifying model is constructed according to the simulated results under different parameters;and a fitting correction function relation is obtained by the numerical method,and the relation is verified.On the basis of this method,the influence on horizontal displacement of piles of different factors are analyzed.(4)Distribution regularities of horizontally loaded super-long piles' vertical friction,tangential friction and normal soil resistance are obtained,and also obtained is the relationship between the three and the bearing capacity;vertical bearing capacities of three test piles are analyzed by combining a project case of a post-grouting super-long pile and static load test;and influences on the ultimate bearing capacity of different factors are analyzed to obtain some certain rules used for providing instructions for engineering projects.