| Based on the National Natural Science Fund of China "Study on bearing mechanism and design method of mixed pile-net composite foundation under embankment"(Project No.50878084)"and analyzing research status at home and abroad, working behaviors for composite foundation with tapered piles were investigated systematically by large-scale model test in the laboratory, theoretical analysis and numerical simulation.1) Based on model tests of one cylindrical wooden pile and three tapered wooden piles with different side obliquity pressed into soft clay ground by static pressure, the laws of vertical displacement of soil surrounding piles and pile jacking pressure were obtained during pile penetration. Then, a comparative test and analysis of bearing capacity of soil surrounding piles was performed.2) Based on the shear displacement method, together with the Mylonakis & Gazetas model for pile-soil mutual action and the E. Winkler foundation model, the flexible factors for pile-pile, pile-soil and soil-soil mutual action were obtained. Considered the performance of the fill, an analysis method on pile—soil—fill mutual action was proposed in the composite foundation under the flexible foundation. In order to validate the feasibility of the proposed approach in this paper, theoretical results were compared with test results. The comparison results showed that the working properties of the composite foundation with the rammed soil-cement tapered piles were much better than that with the rammed soil-cement cylindrical piles under the flexible foundation.3) Based on the FEM software ADINA, three-dimensional numerical simulation of working properties of the composite foundation with tapered piles and cylindrical piles was carried out. The deformation behavior of foundation soil and the differential settlements between pile and soil under different magnitudes of cushion modulus were studied. |
PDF Full Text Request