Abstract
A new composite foundation of pile with soil improved is proposed to resistant intensive seismic horizontal force. Soft soil at the shallow depth is improved by cement mixing method. Piles are constructed through the cemented soil mass in order to transmit vertical loads to bearing stratum. Two in situ horizontal loading tests were performed to confirm their behaviors. It is shown that the horizontal bearing capacity was much greater than that of pile only, and the cemented soil mass and piles worked as a mass when the displacement is less than 1% of the width of the foundation. 3-D FEM analysis is conducted to confirm the mechanism of bearing capacity of the new foundation. A simple design spring model of the composite pile foundation is proposed here.
