The application of small concrete pile without sand in expressway composite foundation;

The background disposal for roadbed and fillings of narrow special and certain section,using the complex groundsill technique of small concrete pile without sand,can reduce roadbed settlement,control the settlement difference and release jump car of the background.

For the expressway widening engineering treated with small non-sand concrete pile,a finite element calculation model is established.

A foundation treatment technology with small non-sand concrete piles is introduced in this paper,including its principle,design and construction process,which is a new-type foundation improvement method and has the advantages of reducing pile usage,shortening construction period and saving capital cost when compared to other foundation treatment methods.

Processing mechanism,methods and processing effects of post-processing technology with small non-sand prepacked stone concrete pile in the applications of widening engineering of expressway are researched and analyzed on the basis of analysis of key problems and common processing method.

In older to resolve the problem of the great amount of cement and the high cost of non-sand cement grounting pile at parent, after testing studies, it is demonstrated that if fly ash is mixed into non-sand concrete by 15%￣ 20% amount of cement, and water cement ratio equal or less than 0.

Mix design of the no-fines concrete grouting pile;

This article adopts orthogonal experiment method to carry out research on resistance press and percolation of no-fines concrete, and mensurates porosity and effective porosity of no-finesconcrete and discusses the formula of calculating percolation co-efficient and analyses the factors that have effect on intensity and percolation of no-fines concrete, the mix proportion for practice is raised.