Study On The Pile Group Effect Under Multidirectional Horizontal Laodings

Usually pile foundation is in the form of pile groups. Model tests of pile groups in sandy soil under unidirectional and directional loadings were performed. Finally the numerical simulation was compared with the experimental results.First, the research of single pile under unidirectional and multidirectional horizontal loadings showed that the force and displacement of each pile was nonlinear, in the case of directional loadings, the maximum horizontal force of each pile was obviously less than the maximum horizontal force of single pile under unidirectional loadings.Then, the results of the pile groups of 3D (D is the pile diameter) along different angle under unidirectional horizontal loadings showed that the force and displacement of each pile in the pile groups were nonlinear, the maximum horizontal force of each pile in the pile groups was less than the maximum horizontal force under unidirectional loadings of single pile test. Along with the increase of load angle, the maximum horizontal force of the front row pile was close to the maximum horizontal force of single pile under unidirectional loadings.After that the results of the pile groups with different pile spacing along different angle under unidirectional horizontal loadings showed that under different pile spacing, the maximum horizontal force of each pile in the pile groups was less than the maximum horizontal force under unidirectional loadings of single pile test. Along with the increase of pile spacing, the maximum horizontal force of the front row pile was close to the maximum horizontal force of single pile under unidirectional loadings. The total horizontal force of the pile groups was increased as the pile spacing increased.And then the results of the pile groups of 3D under multidirectional horizontal loadings showed that the maximum horizontal force was disappeared before the maximum displacement under the figure-8 loading.Finally, based on the results of tests, the change of each pile's horizontal force was simulated. The results showed that the p-y curve of numerical simulation was closer to the experimental results by using the dynamic p-multiplier.