Study On The Optimum Design About The Composite Foundation Integrated By Long Piles (CFG Piles) And Short Piles (Gravel Piles)

Since the composite foundation of dry-vibrated gravel pile and CFG pile has the properties of good safety and economic practicability, it has been widely used in the engineering construction and got the remarkable economical and social benefits. At the present time, its theory and design methods are not very satisfying. With the development of the composite foundation technology, the designers are no longer limited by the traditional design mode, they turn to more and more new technology so as to build the more precise and reasonable theory.The details, such as the reinforcement mechanism and design methods, of the dry vibrated gravel pile and CFG pile were separately introduced at first. And then based on the studies of bearing capacity and deformation, the optimum design model about the composite foundation integrated by long piles (CFG piles) and short piles (gravel piles) double-controlled was built.Relative to the composite foundation with piles of the same length, the composite foundation with piles of different lengths, namely flexible piles (dry vibrated gravel piles) and rigid piles (CFG piles), were demonstrated and analyzed. And the optimum design model double-controlled by the bearing capacity and deformation was built. Furthermore, the practical non-linear programming theory was applied to the resolving of the optimum model built in this paper, and LINGO V9.0 software was adopted to calculate. Finally, on the basis of the study of the foundation treatment of the cooling tower of one power plant, the paper demonstrates that the model built is feasible and effective.The computing formulae of the bearing capacity and deformation of the composite foundation with piles of different lengths, namely flexible pile and rigid pile, have been presented. The results have the actual values to the practice of the composite foundation of long piles and short piles, especially to the composite foundation integrated by flexible piles (dry vibrated gravel piles) and rigid piles (CFG piles). It is also the development and perfection to the study of this kind of composite foundation. The optimum design mode! double-controlled by the bearing capacity and deformation will produce better economic benefits and social benefits in practice.