| dc.description.abstract | Group piles foundation is widely used in public projects, such as wind power generation, oil drilling rig, bridges and nuclear power plants. It is important to consider its dynamic response under seismic loadings. During earthquake, piles deform laterally subjecting to the inertia force of superstructure and cyclic earth pressure of ground. Furthermore, the passive earth pressure of group piles foundation would loss as well as the shear strength when the soil liquefies. Sometimes, the lateral spreading occurs leading to the serious damage of piles. A series of centrifuge shaking table tests in this study was performed to investigate the seismic behavior of group piles with pile cap and superstructure.
According to the test results, the following conclusions can be drown. (1) The maximum bending moment of group piles in dry sand is larger than that in liquefied sand. (2) The maximum bending moment of group piles with pile cap embedded in the ground is smaller than that with pile cap exposed above the ground surface. (3) Subjecting to the small input base acceleration, the bending moment distributions of group piles in dry and saturated sand deposits are almost the same. (4) Under the larger input base acceleration, the soil liquefies and leads to that the maximum bending moment of group piles with embedded pile cap is almost the same as that with exposed pile cap. (5) When the soil liquefies, the excess pore water pressure increases with the increasing depth, and the axial force decreases with increasing excess pore water pressure along depths. After the dissipation of pore water pressure, the axial force increases to as large as that before shaking. | en_US |