Experimental Research on Vertical Bearing Capacity of Composite Piles in Soft Ground

To study the load transfer mechanism,failure mode and vertical bearing capacity of a new-style composite pile formed by inserting a precast concrete pile into a cement mixing pile,in-situ tests of three full-scale composite piles were carried out and axial strains of piles were measured.Based on the experimental results,such as Q-S curves,S-logt curves,limit bearing capacity and axial strain,the distribution on axile force and side resistance of a composite pile,the distribution on side resistance along a composite pile and factors influencing the bearing capacity are analyzed.According to experimental and analytical results,load transfer mode that load is transferred from the precast concrete pile to cement soil and then from cement soil to soil around piles,is formed by inserting a precast concrete pile and the side resistance of a pile is effectively utilized under load.The main sources of high bearing capacity are the solidification effect of the cement soil,the pressing soil effect and the load transfer of the precast concrete pile.A composite pile has higher vertical bearing capacity and low cost,which are its advantage in application in soft ground.