Experimental Study on Bearing Capacity of Bored Piles Using Pile Tip and Side Post-grouting Technology

In view of the vertical bearing mechanism of bored cast-in-place piles and the influencing factors of their bearing capacity,considering the reinforcement effect on pile tip soil and pile side mud cake by compound post-grouting at pile tip and side,the bearing capacity and deformation property of compound postgrouted bored piles in Zhengzhou area are preliminary discussed. By full-scale static loading test on the postgrouted bored piles of a project in Zhengzhou,the improving effect of pile tip resistance and pile side frictional resistance,the load share of pile tip and side by composite post-grouting,and its influence on settlement deformation as well as the whole vertical bearing capacity are researched. The results show that(1) grouting at pile side has improved the mechanical property of interface between pile and soil,which made the resistance of pile side play effectively;(2) grouting at pile tip has reinforced soil layer of pile tip such as sediment layer,which made the resistance of pile tip play in advance;(3) compound grouting has decreased the plastic displacement of interface between pile and soil,which made pile tip settlement slowly and obviously improved the bearing capacity of bored piles.