Research On Vertical Bearing Capacity Of I-shaped Pile Groups

At present,in order to meet the bearing needs of high-rise buildings,high-rise towers,and large-scale bridges,the pile foundation has been one of the most widely used basic forms in civil engineering construction.Based on the concept of green environmental protection,the development of new types of piles has been an important idea in the research of pile foundation engineering.The I-shaped pile is a new type of special-shaped pile,which has the advantages of simple production process,good economic benefit,high bearing capacity,good generalizability and so on.At present,the relevant theories and experimental researches on I-shaped piles are relatively lacking,especially,the influence of the upper load on the interaction between I-shaped pile groups is not considered,and there is a certain gap between the current engineering application requirements.Based on this,this paper through the indoor model test of I-shaped pile groups,combined with ABAQUS finite element software to analyze,discussed the bearing capacity and load transfer law of I-shaped pile groups foundation under the vertical load,and relevant engineering suggestions were put forward.The main research contents and results are as follows:(1)Through the indoor model test of the I-shaped pile groups,we obtained the load settlement curves at the top of the pile cap,the axial force curves of the center pile,the side pile,and the corner pile,and inferred side friction resistance of each pile from axial force.The results showed that the load-settlement curve of the I-shaped group piles was slow-changing;the load sharing of each pile top was: the corner pile> the side pile> the center pile,the corner pile friction resistance played the most.(2)The indoor model was simulated by ABAQUS finite element software,and the reliability of the model was verified by comparing with the experimental results.Through analysis of pile top axial force and pile side resistance,it was found that the force distribution of long side piles and short side piles was basically similar.(3)By analyzing the influence of different pile number and pile spacing on pile soil interaction,it was found that the average bearing capacity of single pile decreased with the increase of pile number.With the increase of pile spacing,the load shared by each pile tended to average,the best reasonable pile spacing was 4b-6b in the long side direction,and the short side direction is 4h-6h.(4)According to the results of finite element analysis and the calculation method of relevant theory,we put forward the formulas of vertical bearing capacity of single pile and group pile,and discussed the range of correlation coefficients,such as the reduction coefficient of rectangular section,the reduction coefficient of the type section,the effect coefficient of group pile and so on.