Application Research On Combined Vacuum-Surcharge Preloading Method In Treaating Soft Soils At The End Of The Bridge

Soft soils foundation treatment technique of highway is an effective measurement for prevention vehicle bump at the bridge end. Recent years, combined vacuum-surcharge preloading method is becoming a popular soil improvement technique especially for soft soils, its mechanism of reinforcement, construction technology and effect are pay more attention by large numbers of technician and investigator, much devotion are put into how to settle down the common symptom of vehicle bump at the bridge end. For this reason, this paper is concentrated on the reinforcement mechanism, construction technology, field testing, reinforcement effect of combined vacuum-surcharge preloading method as well as its technical and economic practicability, the application of this method using to treating soft soil at bridge end are introduced particularly, the main research work are listed below:(1) In this paper, both domestic and overseas literatures about soft soils treatment with combined vacuum-surcharge preloading method are reviewed, its development actuality and direction are presented.(2) The mechanism of soft soils roadbed reinforce technique using combined vacuum-surcharge preloading method are deeply analyzed after compared with heaped load preloading method.(3) The construction technology and its characteristics are summarized based on given highway embankment project, at the same time, field testing results including ground surface settlement, lateral displacement and pore-water pressures are investigated thoroughly, its effect are also summarized.(4) Combined vacuum-surcharge preloading method is proved to be an effective and reasonable method after detailed technique and economy analysis in treating soft soils at the end of the highway bridge. Combined vacuum-surcharge preloading is proved to be a feasible and valid method for its dual action of vacuum preloading & heaped load preloading on the basis of research fruits, it can be generalized as a good method in prevention and treatment of vehicle bump at the bridge end.