Cfg Pile Composite Foundation In The Zhengzhou Taohuayu Yellow River Gate Project

The CFG pile (Cement Fly-ash Gravel pile) is one main kind of rigid complex foundation and it has been authorized as nationally recommended method since 1997 .The . Remarkable technical, economic and social benefits have been gained through the widely application of CFG pile complex foundation in civil engineering and road foundation treatment. However this method has seldom been used in the Hydraulic engineering works and especially has never been used in the Yellow River water supply engineering works.The foundation of Taohuayu Yellow River sluice works was originally the main channel of the Yellow River thus the foundation is typically the loose sand. The structure of the Sluice is very complicated due to the limitation of performance function, which makes the nonuniformity of the plan layout and rigidity distribution. The foundation bearing capacity requirement is very high because of the working loads include dead load, side earth pressure and water pressure and etc.. Coefficients of nonuniformity subgrade reaction and foundation stress are calculated on the conditions of completion period, design water level and highest operation water level of the Yellow River sluice . According to the site geological condition, requirements of the foundation treatment method are brought forward.According to "Technical code for ground treatment of buildings", comparative study and optimum study have been conducted for different foundation treatment methods of Taohuayu Yellow River sluice works and finally the CFG pile complex foundation treatment method is designed.. Feasibility and rationality of the theoretical design are validated through single pile complex foundation load test, single pile vertical steady load compression test, low train test.Satisfied results have been gained to treat loess collapsibility and to improve foundation bearing capacity, especially when bearing stratum is sand and is probably be scoured since it gets closely to the main channel of the Yellow River. Drilling the CFG pile into the stable stratum can effectively solve the problem of losing the stability because of the scouring. It is a kind of effective method to treat the loose sand foundation.