Study On Bearing Capacity And Influence Factor Of Pedestal Bored Pile Compacted Column-hammer

Pedestal bored pile compacted column-hammer is a new type of pile which isdeveloping from the column hammer pile method. on the one hand, the pile make the bottomsoil compaction effect through the packing tamping, and improve the physical andmechanical properties of the soil; On the other hand when the bottom soil of the pilereaching a certain compactness, The filler will be squeezed around the hammer and thebottom, then forming a certain height, diameter of approximately spherical thick compactionof body. Through the above two reasons, the capacity of the pile can be improved greatly.There are three parts in this paper: field excavation test, model test and finite elementanalysis.Excavation tests showed that, when calculate the Carrying Capacity of the pile, it canbe assumed Rammed body is spherical, derive the level projection area ADby the dryconcrete volume VH, then correcting the value by the correction factor ɑDwhich is rangingof0.8~1.0.Based on the test site excavation through model tests of different hammer shapes,different soil density, the effects of different parameters on the construction Rammed bodyshape. The results showed that:first, column hammer ramming reamed pile to pile endbearing capacity, in the actual project can choose concave hammer construction, caneffectively increase the bearing capacity of pile end soil. second, the effects of four kinds ofhammer type of ram compaction body shape, the concave hammer the ram compaction bodyhorizontal projection area is the largest, so the construction column hammer existed inconcave hammer is the best choice. Three, in the test soil layers of different density, the ramcompaction body is spherical, the size is not the same as the only. In the end of pile for softsoil, filler amount is large, the ram compaction body horizontal projection area is large, thecorrection coefficient can be large value, pile end as the hard soil filler volume is small, berammed horizontal projection area is small, the correction coefficient can be appropriate forsmall value.Using ABAQUS software, finite element simulation for the column hammer pile, drawthe following conclusions: first, in the ram compaction body consistent size and shape, pileend soil properties under the same conditions, the longer the pile foundation pile bearing capacity increases, but the capacity is improved greatly. Two, in the bearing layer is silty soil,compaction volume under the same conditions, the spherical bearing capacity of ramcompaction body highest, lowest cylindrical ram compaction body bearing capacity. Three,RAM compaction body volume increases the bearing capacity of the pile foundation ishigher.