Study On Applicability Of Long Auger Drilling Pile And Screw Concrete Pile Based On Nanning Typical Stratigraphic Combination Model

Based on the stratigraphic assemblage model of Nanning basin,the applicability of long auger bored pile and thread pile is studied in this paper.To this end,the test team lasted more than a year to choose in two of the same stratigraphic combination of two similar design parameters of the test pile for the corresponding engineering test.And the detailed analysis,calculation and research are carried out from the bearing mechanism,construction control,technical characteristics and engineering test results of two types of piles.Draw the following conclusions:(1)The long auger bored pile and screw concrete pile are in the practice of small and medium diameter pile,the two types of piles in the construction process,pressure irrigation concrete,steel cage implantation,site construction and other aspects of civilization has the same or similar characteristics.But in the bearing mechanism,into the pile of machinery,piles of quality control points,the cost difference between the larger.(2)It is difficult for the two types of pile-forming equipment to accumulate into the rock,but the long auger bored pile can not only reduce the bearing capacity of the single pile but also improve the bearing capacity of the single pile.When screw concrete pile is difficult to rock(or drilling),the bearing capacity of its single pile is greatly affected.(3)Through two kinds of similar formation site design parameters of the pile test,long auger bored pile by selecting a good pile end force layer,the appropriate increase in concrete pressure irrigation,can significantly improve the bearing capacity of single pile.And the screw concrete pile in the thread into the hole or into the pile process,if you can not use the synchronization technology,as a single pile bearing capacity of the main source of the thread section bearing capacity decreased significantly,the bearing capacity of the site only when the pile 46%about.(4)When the soil of the screw thread is disturbed,the pile side resistance of the screw thread is equivalent to the pile side resistance of the dry pile of the dry pile with the diameter of the pile,and through the analysis of the test result parameters,The formula of the lower limit of the bearing capacity of the single pile is put forward.(5)If you reduce the depth of the rock pile into the rock to ensure the normal formation of the thread,the application of the pile in the foundation treatment has a comparative advantage.(6)At the present stage,the long-auger bored pile has better applicability than the screw pile in the typical combination stratigraphy(I and II terraces)in the Nanning basin.The applicability of the two types of piles in the high-grade(mudstone)stratigraphic assemblages in the Nanning basin is poor.