Research On Behavior Of Bearing Capacity Of Expanded-Foot Tubular Pile By Static Pressure Method

Expanded-foot tubular pile by static pressure method is composed ofprestressed concrete tubular pile and expanded-foot. It makes use of thehollow characteristic of tubular pile in order to press concrete on thebottom of the pile to form the expanded-foot. It takes advantage ofprefabricated pile and rammed pile without the phenomenon of broken pileand necking. The pile has the advantage of high load-bearing capacity andlow settlement. It is very suitable for the pile to be used in soft-soil areaswhich has the good economic and social benefit. However, there are stillsome problems both in theoretical research and practice such as thecharacteristics of the stress and strain, improving of bearing capacity whichneed the further study.Several aspects are studied such as the forming mechanism ofexpanded-foot, behavior of bearing capacity, improving of bearing capacity.Firstly, the construction technique and application range are introduced inthis paper. Then, the forming mechanism of expanded-foot is analyzed. The shape of the expanded-foot is obtained by the model test, and the bearingcapacity between expanded-foot tubular pile and the equivalent-diametertubular pile is analyzed, as well as the bearing capacity among the differentdiameter expanded-foot tubular pile, the compaction effect and range topile end soil layer are studied, the reason of load bearing capacityimproving is pointed out. Combining the actual behavior, bearing capacitycalculation of expanded-foot tubular pile can consult the calculationmethod of rammed pile, but the correction coefficient of compaction isdifferent. The different diameter expanded-foot tubular pile and length ofpile are compared by using the program ANSYS for finite element analysis.The result can provide a general recognition on behavior of bearingcapacity and the theoretical basis for actual behavior.