Research Of Design And Construction For Cement Flyash Gravel Pile Composite Foundation In Highway

This paper reviews the engendering procedure and development of Cement Flyash Gravel pile , induces the works characters of CFG pile composite foundation . On the base of this, analyzes the reinforcing principle, analyzes the method to calculate the composite foundation ultimate capability with the formula of area ration and the formula of stress ration, and analyzes the calculation method of CFG pile composite foundation ultimate capability.At the same time, this paper analyzes the present situation of settlement calculation of CFG pile composite foundation, compares all the settlement calculation methods, and put forward the adaptation. The relation between composite model and foundation ultimate capability feature value, then gets the practical formula of settlement calculation of CFG pile composite foundation. Cushion technique is the un-lack important technique in CFG pile composite foundation, during setting cushion and construction, it must be considered overall according to the actual condition of works and the site, and develop its proper benefit.Based on the basic principle of FEM analyzing method, this paper introduces the system model, basic steps to solve problem, the function and technique charactersof the great common FEM software-ADINA . Simple method is adopted whilecalculating the CFG pile composite foundation, on the base of this, establishes the FEM analyzing model of single pile ultimate capability, analyzes the calculating steps of ADINA FEM calculation in details, and gives calculation model. The calculation results are arranged and compared with the P-S curve surveyed in site, the comparing makes clear that the nature tendency of calculation results of ADINA and surveyed data in site is identical on the whole, and the ration value is near.Combining with the development survey of CFG pile composite foundation construction technique, this paper compares the advantages, disadvantages and applying condition of two construction techniques which are vibrating and settling pipe method and pumping Cement Flyash Gravel in long spiral pipe method. Then with the example of Maixinlu cross overpass transition segment in forth contract segment of Jing-cheng highway which adopts the construction techniques to deal with the foundation with pumping Cement Flyash Gravel in long spiral pipe pile, analyzes the construction essentials and quality controlling measures of pumping Cement Flyash Gravel in long spiral pipe pile, it can offer a set of complete reference data to the construction of similar works.