Research on the Additional Stress and Deformation in the Soil of Composite Pile Foundation under Vertically Uniform Loads

The behavior of composite pile foundation is different from that of common pile foundation, which has not been understood fully yet. Therefore, this paper was designed to analyze the additional stress and the deformation of soil in composite pile foundation. The finite element method was applied to simulate the performance of pile foundation under vertically uniform loads. And the classical Boussinesq's solution was used to calculate the additional stress. Some cases were presented to compare the behavior of composite pile foundation and common pile foundation. The calculated results show that the biggish additional stress exits in the soil between piles and the stress along the pile is uniformly distributed. It is certain that the soil between piles shares a certain part of loads transferred from superstructure. Hence, it is suggested that the additional soil stress between piles and under piles should be considered to calculate the settlement of composite pile foundation. On the base of above suggestion a simplified method of calculating the composite pile foundation settlement is presented. The case comparisons demonstrate that the results of simplified method presented in this paper have a good agreement with the test date.