A series of model tests was conducted to compare the horizontal bearing capacities of longitudinal section shaped pile (belled pile and tapered pile)

and traditional equal-diameter pile

which have identical volume of concrete. The distribution of the internal force and deformation of piles

the ultimate bearing capacity

and lateral soil pressure were measured under different levels of horizontal load. The distribution of the ultimate bearing capacity and lateral soil pressure of three different pile types were comparatively analyzed. A theoretical method was developed to calculate the lateral bearing capacity of longitudinal section shaped pile based on p-y curve method and by considering shape effect. The distribution of pile moments and influencing factors were discussed. The results show that the horizontal bearing capacity of tapered pile is larger than those of belled pile and equal-diameter pile with identical volume of concrete. The ultimate horizontal bearing capacity of tapered pile embedded in sand and clay is nearly 1.25 times and 1.33 times of that of equal-diameter pile. These experimental results are useful for practical engineering and analysis of longitudinal section shaped piles in different applications.