Study On Mechanism About Rebound Of Pretest Piles And Controlling

Recently, reinforce and reconstruction of building is greatly attach importance to in and out and developed into a new science. However, in treating building disease on function reconstruction, story-adding reconstruction of existing building or settled, cracked, slope etc., most of them related to ground and basement treatment and reinforce of existing building. Practice proved, is really an effective reinforce method of ground and basement, especially used in collapsible loess region. But presently, theory research is little in this technique, construct technique still need improved, thereinto rebound mechanism and controlling of pretest underpinning piles is a badly in need of settled research problem.According to load transfer method, finite element method and static loading test method etc., combined project, this paper synthetically analyzed and researched rebound mechanism and controlling method of pretest underpinning piles, four results are obtained: (1)In process of pressing piles, top and sub soil surrounding pile existed elastic region and plastic region respectively; (2)Rebound mechanism of piles is due to enclasp piles force which produced by radial press force, sub-soil surrounding pile which produce up-friction in elastic region and elastic resilience on support layer of bottom pile; (3)Proportion relationship consist in rebound and rebound force ,underpinning press ; (4)According to control underpinning press ,support layer of bottom pile and improve press piles and underpinning of pile technique ,it can turn control rebound of piles method into reality.Above research results have better reference value for further study mechanism of pretest underpinning pile, analyze and decide bearing capacity and better improved technique. Moreover, it gain better applied effection in project.