Abstract:To study the ladder-shaped variable section pipe-pile composite foundation load-bearing characteristics, conducted on indoor large scale model contrast experiments the bearing properties of two groups of uniform section pipe pile composite foundation and three groups of ladder-shaped variable cross-section pipe pile composite foundation. The conclusions show that: under the same loading, the settlement of ladder-shaped variable cross-section pipe pile and its composite foundation is obviously less than that of uniform section pipe pile. On the condition that the amount of pipe pile materials and geological conditions are the same, the single pile stiffness of ladder-shaped variable cross-section is significantly greater than the stiffness of uniform section single pile. The strength of ladder-shaped variable cross-section pipe pile is coordinated with the variation of axial force of pile shaft. Therefore, adopting ladder-shaped variable cross-section pipe pile makes full use of pile strength and reduces the cost of the pile.