Analysis of Surface Vibration Response Induced by PHC Piles Driven into Non-Uniform Saturated Soil Layer

The current theories on pile driving vibration are based on localized theories. Therefore, the objective of this paper is to consider the gradient variation of porosity along the depth in relation to the depth of pile driven into the soil layer in the framework of non-local theory. The ramming energy parameter is introduced to improve the model of gradient variation of porosity along depth. The coupled analytical solution is proposed of surface vibration induced by steel pipe pile driven into nonuniform saturated soil layer by the porosity is coupled with density, shear modulus, Lamé constant and permeability coefficient, and coupling the tamping energy parameter into Eringen’s nonlocal theory and Biot’s theory of saturated porous elastic medium, and combining the mass conservation equation, momentum balance equation, and effective stress principle. Analysis the change rule of impact energy attenuation degradation and the influence of surface vibration deformation during the process of PHC pile driving into non-uniform saturated soil layer. The results of the study show that the influence of soil uneven gradient parameter on soil parameters is greater than that of energy parameter. Pile driven into the non-uniform soil layer at any depth location, uneven gradient parameters and energy parameters under the increase, the horizontal amplitude of surface vibration, vertical amplitude decreases. However, the horizontal amplitude and vertical amplitude of surface vibration increased with the increase of soil skeleton geometry parameter. The analysis shows that the energy parameter has the greatest influence on the horizontal and vertical amplitudes, the soil skeleton geometry parameter has the second greatest influence on the horizontal and vertical amplitudes, and the non-uniform gradient parameter has the least influence on the horizontal and vertical amplitudes. The results of the study can assess the problem of surface vibration response induced by pile driving construction, but the theory is a result of the study carried out in the framework of nonlocal elasticity theory, which still needs further improvement.