Vertical vibration of a single pile embedded in a frozen saturated soil layer

Abstract

The theories of elasticity and a composite solid-phase saturated porous medium were employed to investigate vertical vibration of an end-bearing pile embedded in a frozen saturated soil layer from three-dimensional axisymmetric analysis. Analytical solutions to the dynamic responses of the pile were derived by Helmholtz decomposition and variable separation in the frequency domain. The solution to the pile in a frozen saturated soil layer agreed well with that in saturated soil when the temperature was close to the frozen temperature. The resonance model of the soil layer induced by the pile vibration was established and the influence of the longitudinal waves and transverse waves caused by pile vibration on the resonance modes was depicted. Complex impedance of the pile top was presented to illustrate the effects of the freezing temperature, porosity and shear modulus of unfrozen soil. The results showed that the maintaining freezing status technology was still valid for pile vibration in permafrost over a larger frequency range; however, it might be invalid in a very low frequency due to the ice skeleton formed below the frozen temperature of the soil.