The Application Study On Pile With Bearing Base In Dense Sand Stratum Of Zhengdong New District

Carrier pile with the construction of simple, high capacity, good pile quality, low cost, andhas broad application prospects. Dense sand is a good foundation of the building, with a highcapacity, low compressibility, permeability and good. Although the carrier and the carrier pilefoundation pile composite foundation in engineering practice sand layer was successful, but thetheory is still relatively small, in order to explore and promote its use results in a stratum of sand,for such geological conditions Download bodies pile bearing capacity, research and improve thereliability theory is very necessary, for future similar projects pile carrier design and constructionof the project to provide a reference.In this paper, Zhengdong new district with high-rise buildings in the background test piles,using theoretical analysis, research vehicle pile static load test method, numerical simulation ofsedimentation characteristics in dense stratum of sand, bearing properties, mainly to do thefollowing work:1．Theoretical analysis of the mechanism of the carrier bearing piles, failure mode, loadtransfer law and the expansion of the head mechanism of action, and a summary of itscalculation of the vertical bearing capacity.2．Low strain dynamic test method to determine the carrier pile body integrity; through thestatic load test, take measurements of field data on bearing characteristics in dense sand stratumcarrier pile conduct research and comparative analysis of the test results and the calculatedresults differences.3．Use Abaqus software to establish carrier Pile finite element model consistent with theactual project, the simulation results of stress and displacement analysis, and analysis of itsvertical bearing capacity factors.By studying the test, numerical simulation methods such as static load, get major results areas follows:1．Carrier sand piles and dense stratum has good matching, this paper pile ultimate bearingcapacity can reach4500KN, is also the first carrier in the domestic meters height pile buildingsuccessful test. 2．When loading the carrier pile foundation pile vertical bearing capacity of approximately1.5times the calculated value, As curve will be steep drop changes, dense sand pile side havelost or basic loss of elasticity, pile piercing destruction is likely to occur.3．In the dense sand stratum, the carrier pile foundation by "carrier pile design procedures"(JGJ135-2007) vertical pile capacity calculated values are too conservative, is not conducive tothe construction economy.4．Compared with the carrier vehicle pile composite foundation pile foundation, whenloaded to its norms were calculated value, due to the role of composite foundation cushion, theformer settlement of pile accumulated value is greater than the latter.5．In the pile material is unchanged, by changing the pile diameter to increase the carrierbearing piles ineffective.6．Engineering support optimal Rammed pile diameter should be controlled between800~1000mm.