|
Abstract Model test is a necessary scientific method which is used in the research on bearing performance of pile foundation. The differences of bearing capability of piles using different piling techniques are significantly studied through designing model test and analyzing test data，and the influence of unloading effect caused by cavities drilling to bearing mechanism of bored piles，as well as the mechanical and settlement property of piles，are also discussed by comparative analysis. The study indicates that：Q-S curves of test piles appear steep drop type；the bearing capacity of jacked pile is the most prominent of all，but less obvious in pre-buried pile and bored piles in steep performance. The load transfer performance of test piles will be affected by different construction methods，and the load transfer capability of jacked pile in the depth direction is worse than that of pre-buried pile and bored piles due to the difference between compacting effect and unloading effect. The skin frictions of four piles are intensified in certain depth，and the strengthened position of jacked pile is slightly higher than that of bored piles and pre-buried pile，which is caused by the fact that compacting effect makes skin friction increase. Otherwise，unloading effect caused by cavities drilling of bored piles and the backout of film wrapped around pre-buried pile weakens skin friction to a certain extent. The extremum exertion and extreme points location of skin friction of piles are highly influenced by different piling techniques. Skin friction and tip resistance do not display in identical time and do not achieve maximum at the same time；and the proportion of tip resistance in total working load varies with upper load.
|
|
Received: 28 November 2011
|
|
|
|
2012, Vol. 31 
