Study On The Theory And Method Of CFG Pile Composite Foundation Design Review

CFG pile composite foundation has been widely used in engineering because of its high bearing capacity and low cost.However,in actual engineering,"the composite foundation bearing capacity meets the design requirements,and the single pile bearing capacity does not meet the design requirements" often happen.When the pile has good integrity,the design value of single pile bearing capacity is too large,which is the main reason that the bearing capacity of single pile does not meet the design requirements.The relationship of the interpile soil bearing capacity factor ? and the single pile bearing capacity factor ? is the intrinsical reason.In this paper,according to ABAQUS building the CFG pile composite foundation model,analysing the relationship between the interpile soil bearing capacity factor ? and the single pile bearing capacity factor ?,proposing the method of single pile bearing capacity design review,solving the problem of "the composite foundation bearing capacity meets the design requirements,but the single pile bearing capacity does not meet the design requirements".The main findings are as follows:(1)For piles with good integrity,the basic reason why the bearing capacity of the single pile does not satisfied is related to the interpile soil bearing capacity factor ? and the single pile bearing capacity factor ?.(2)Using ABAQUS to establish the CFG pile composite foundation model of the cushion under unconfined conditions,studying the relationship between the interpile soil bearing capacity factor ? and the single pile bearing capacity factor ?,and analyzing the influence of load and cushion thickness on the bearing behavior of CFG pile composite foundation.The results show that when the cushion layer is under the condition of no confinement,? is increased as ?.?'s value range is 0.91 to 0.96,?'s value range is 0.95 to 1.00.(3)Establish the solid model of CFG pile composite foundation under the action of confined conditions,and further study the relationship between ? and ? under the condition of confined conditions,so that the conclusions of finite element simulation are more sufficient.The results show that the ? of the ruthenium under the confinement condition increases with the increase of ?;the value of ? ranges from 0.92 to 0.97,and the range of ? ranges from 0.96 to 1.00.(4)The method of designing the bearing capacity of single pile of CFG pile composite foundation is proposed.By continuously adjusting ? and ?,the design value of bearing capacity of single pile meeting the requirements of the specification is obtained,so as to solve the problem that "the composite foundation bearing capacity meets the design requirements,and the single pile bearing capacity does not meet the design requirements".In addition to saving a large amount of processing fund and time,the design review of single pile bearing capacity also objectively reduces unnecessary engineering disputes and provides a basis for similar projects in the future.