Research On The Bearing Capability And Design Theory Of Sand Compaction Pile Composite Foundation

Sand compaction piles are applicable widely in kinds of foundation such as incompact sandy soil foundation ,silty sand foundation,clayey soil foundation,filled soil foundation,and simplex filled soil foundation.Especially in the treatment of sandy soil foundation,because of the low cost ,prominent effection and successful experience of this method .Because sand compaction pile is a kind of incompact material pile,Thus it is very different from partial rigid concrete pile in piles with soil characteristics and damage mechanism .In the actual design there are some difficult problems in the calculated theory and engineering construction.This paper summarizes the recent compacted sand pile composite foundation theory, engineering experience and their development status. Applicating finite element analysis software for numerical simulation, the simulation results are analyzed.For the foundation for different circumstances, given the corresponding approaches and programmes.First this paper discussed the distant between interfacing piles, the pile length, pile fabrics, material selection , whether selecting cushion and the impact of the bearing capacity;Second,the pile bearing capacity calculation method and the destruction of the form was discussed .If the load in the top of the pile is large enough, the damage will occurred in piles .There are three possible failure modes: bosomy damage, penetrating destruction and shear failure. As piles of rubble are composed by loose particles, Bearing capacity of piles depends primarily on the lateral capacity of soil between piles ,The overwhelming majority of the damage form is fish-bellied damage .There are a few kinds of calculated method of gravel pile at home and abroad .Such as the lateral limits of stress method,whole Shear failure method,Expansion of the orbicular hole method,and so on .this paper will discuss the Brauns method and comprehensive ultimate strength analysis method, and other methods of calculation .Next the method of composite foundation bearing capacity will be discussed.The foundation bearing capacity eigenvalue of Piles of gravel ,shuold be determined through the scene of the foundation load test .When preliminary design, also can be estimated based on some theory. Using Flac3D application software establish a number of simulation contrast for the analysis of different factors on the bearing capacity of composite foundation.Next the settlement calculation methods will be discussed in this paper.The settlement calculation of piles of gravel includes the strengthening district of foundation and settlement of reinforcement areas .Principal law can be according to Lamination method of summation and settlement discount law.Finally for different geological circumstances ,the construction methods are sumed up and studied base on some engineering instances.