Rigid Pile Composite Foundation Under Flexible Foundation Pilot Study

Compound ground technology in architectural engineering widespread application, not only impelled under the rigid foundation condition compound ground technology day after day mature, but also causes the related supporting capacity design and the distortion computation theory consummates day by day. In recent years, the compound ground technology application scope expanded to the traffic engineering, this article proposed under the roadbed condition compound ground supporting capacity and the distortion estimation problem. Compares with the rigidity of construction foundation, the rigidity of reclamation roadbed is weak many, result in Supporting capacity and distortion characteristic between Under roadbed condition compound ground and Under rigid foundation compound ground is disparate. The research roadbed (flexible foundation) under the condition compound ground load bearing performance, to fills high under the roadbed condition ground processing design theory establishment, has the important project significance and the scientific significance.This article unifies some section of paths to expand the width project of Lian-Huo highway, designed 4 pile compound ground to carry on the scene static load experiment under the flexible foundation condition. Vertical enhancement body type including static pressure reinforced concrete steel pipe driven in as piling and CFG pile.The experiment from bottom to top uses 300mm thickness sand-gravel cushion,500mm thickness soil cement endo plus two layer geotextile,1500mm thickness sandbag layer, then anew aloft layer plus try counterweight mode came simulation flexibility roadbed loading environment. Yields the series experiment result to be as follows:(1) Flexible foundation down rigid dolphin multiply foundation pile earth stress ratio numerical value farther less than rigid foundation down pile-soil stress ratio cost.The change law of pile-soil stress ratio under flexible foundation down pile-soil differ from rigid foundation's. Actual measurement with the result that , pile-soil stress ratio abaft urge infancy in favor of, in company with load increase, undulate change, eke , undulate change, aback again gradualness advance out.(2) Because the flexible foundation compound ground its rigidity is small, the pile body easy to prick upwardly, after in addition the foundation bed stress cannot maintain the plane, this has adjusted the stress assignment between the pile and the pile, caused under the flexible foundation between the pile the soil body to undertake many loads, the soil body has been before the pile body to achieve the limit destruction load. Therefore the destruction pattern of the flexible foundation compound ground and the rigid foundation compound ground is completely different.(3) Under the flexible foundation the pile body peak provides the friction force hasprevented the soil body distortion, also because the soil body undertake many the load, the vertical pressure high, in addition the pile body lateral restraint, the soil body in three to encircles presses the intensity natural foundation to enhance largely.(4) Under the flexible foundation condition the rigid pile compound ground needs the enough rigid breaker strip to improve its work character effectively. the experiment indicated ,It can enlarge the stress ratio of pile to soil when using certain intensity the breaker strip and establishing the appropriate driving cap. When uses this measure, to the common roadbed project, the rigid pile compound ground may profit from the rigid foundation condition methods design.