A Numerical Study On Bearing Capacity Behavior Of Super-long And Large-diameter Bored Pile Groups

Recent years,with the development of Chinese economic,high-rise buildings andlarge bridges are more and more popular. Since the load given to foundations largerand larger,the traditional short piles can’t bear.In this condition,especially in regionsof soft soil, the use of long large-diameter bored piles represents the generaltrend.However,the theoretical research on it cant’t meet the practice requirements.Itsdesign theory is based on short small-diameter piles and past experience.People don’tfully understand how load transfer yet.So it is necessary to analyze the verticalbearing capacity of long large-diameter bored piles and the effects on it of differentfactors.This paper first analyzes the long large-diameter single pile calculation theory. Onthe basis of it,the paper studys the effects of different factors on pile groups.In thisway,we hope to simulate the practical stress state of pile foundation and give someuseful conclusions.Specifically,we first introduce the research status and the relatedstandard of long large-diameter bored pile and tell the main content of this paper.Thenwe build the single pile model through Flac3D software base on the theory of finitedifference method.During the time,we make the single pile Q-S curve. We analyzehow the tip resistance and lateral resistance change with pile top settlement,how thepile side friction resistance change with pile embedded depth,the distribution of pileaxial force,the compression of pile.After that,we study the effects of various factorsincluding pile length,pile diameter,elastic modulus of soil,soil angle and cohesion onthe bearing capacity of single pile.In addition,a new method is proposed fordetermining single pile effective length method.Based on the analysis of singlepile,we give a research on the vertical bearing capacity of long large-diameter boredpiles,the distribution of pile top load and the effects on it of different factors. Finally,the article make a brief analysis of the pile horizontal bearing capacity.By such study,we can give some useful calculation theory in practice.