Bearing Capacity Study Of Branch Pile Under Vertical And Horizontal Load

Branch pile is a new type of pile according to bionics principle, which is developedbased on original regular cast-in place pile with constant section. With high loadingcapacity, good build-in nature, good techno-economic indicator and more otheradvantages, it is widely applied in a variety of engineering construction projects.Presently, most of the studies on branch pile focus on its single capacity of vertical ortransverse loading, however, there are seldom pile foundations used in practicalengineering simply bearing horizontal or vertical loading. Apart from bearing thevertical loading from superstructure, most pile foundations also have to bear thetransverse loading that can’t be ignored. Thus, the research on the bearing capacity ofbranch pile under combined action from horizontal and vertical loading has importantsignificance.The bearing capacity of pile foundation when it stands bidirectional load isextremely complicated, for its bearing capacity is not only related to the material of thepile, but also is largely dependent on the performance of soil around pile. Based on theprevious studies on branch pile, combining with domestic and foreign research, indoormodel tests of branch pile are conducted on single horizontal loading and combinedaction from horizontal and vertical loading according to similarity theory.Through relevant data collected from the strain foil pasted at the suitable positionof branch pile body and the soil pressure cell buried in the soil around pile, load transfermechanism of the branch pile and the pressure change of soil around pile arecomparatively analyzed under the action of horizontal loading and combined actionfrom horizontal and vertical loading.In addition, on the basis of model test results, using the symmetric structure of thefinite element analysis, finite element analysis model is established. Focused on thebranch pile in the form of two different loads, parameters of pile around soil and elasticmodulus of pile are analyzed. The result shows, the pile top horizontal displacement is less than the branch pile only to withstand horizontal loads, when the branch pile isunder vertical and horizontal load, the horizontal bearing capacity can be increased to acertain extent by the existence of vertical load. The capacity of branch pile under twodifferent loads can be improved with the increasing of soil cohesion, angle of internalfriction, pile modulus of elasticity and modulus of elasticity of soil.