The Research Of Raft Foundation Anti-floating Piles' Performance And Its Impact On The Raft Foundation

With the development of cities,the space got great development and utilization of underground structures,ultra-large and ultra-deep underground structure growing,its anti-floating problem is becoming more and more prominent.Especially in the coastal and shallow underground water level area,it requires more economic and efficient anti-floating measures.In the past,the anti-floating design of underground building foundation is used mostly the bored piles,but the connection of bored piles and column makes the uplift pile spacing is too large,and needs thick slab to resist the bending moment and shear force to the groundwater buoyancy,so the cost is high and the economy is bad.But recently,the anti-floating pile with its good anti-uplift performance and convenient construction is getting more and more good graces of the underground engineering designer and constructor.At present,the anti-floating pile load transfer mechanism and the calculation method is not mature,and its theoretical research is not system.Due to the anti-floating pile test's long cycle,high cost and complex mechanism,there are few engineering field test is used to determine the bearing capacity of anti-floating pile.Most of anti-floating pile engineering is mainly using the method of uplift pile to determining the ultimate bearing capacity of the anti-floating pile.The limit of research to factors affecting the anti-floating single pile's bearing capacity and the methods to improve the bearing capacity of it are not mature.And,the anti-floating pile is regarded as more temporary anti-floating auxiliary facilities in current projects and so on the later study of the effects of raft foundation is very rare.But in actual engineering,anti-floating pile has more and more widely application prospects,so research on the mechanical behavior of raft foundation anti-uplift pile appears very urgent,and it is of great practical significance.In this paper,based on the summary of a large number of literature material of raft foundation and the anti-floating pile,on the basis of the interaction theory and analysis method,using pile-soil entirety finite element analysis method to study.In this paper,we using finite element software ANSYS and ABAQUS to set up anti-floating pile and raft foundation calculation model respectively and using numerical analysis method to study the influencing factors of bearing capacity of anti-floating pile and mechanical properties of raft foundation anti-floating pile and its impact on the raftfoundation lately.Through the study of this article,we carried on the detailed elaboration to the mechanical properties of the raft foundation anti-uplift pile,laid a certain foundation for follow-up study.We obtained anti-floating pile load displacement curve by finite element calculation,got the general influence law of the anti-floating pile bearing capacity factors;By comparing the influence of different pile spacing to the internal force and displacement of anti-floating pile,we can got different impact trend of the mechanical properties of the raft foundation anti-floating pile,thus we can concluded the optimal arrangement scheme of anti-floating pile in general condition,and provide a new thought of design and reference date for the future anti-uplift design.