Numerical and test study on vertical vibration characteristics of pile group in slope soil topography

Topography effects on the vertical vibration responses of pile group are revealed though numerical analysis and model tests. First, a series of model tests with different topography of ground and bedrock are conducted. The results indicate that displacement amplitude of the pile head in sloping ground topography is larger than in horizontal ground. Differential displacement at various positions of the pile cap is observed in non-horizontal topography. Afterwards, a numerical algorithm is employed to further explore the essential response characteristics in group piles of different topography configurations, which has been verified by the test results. The lengths of the exposed and frictional segment, together with the thickness of the subsoil layer, are the dominant factors which cause non-axisymmetric vibration at the pile cap.