Study on Longitudinal Vibration Characteristics of Cored Pipe Pile Under Groundwater Level Fluctuation

According to the fluctuation of groundwater level, the coupling dynamic characteristics of cored pipe pile and soil under longitudinal vibration load are studied. Considering the soil at the pile end as a virtual soil pile, the vibration equation of soil layer and cored pipe pile under the influence of groundwater level fluctuation is established, and the dynamic equation is decoupled and solved in combination with boundary conditions. The analytical solution of frequency domain response and semi-analytical solution of time domain response of dynamic coupling between cored pipe pile and soil are obtained. After the pipe pile is reduced to solid core pile, it is compared with the existing theoretical solution of solid core pile, and then compared with the numerical solution. Finally, the effects of groundwater level change, core filling material and core filling height on the longitudinal vibration characteristics of core filled pipe pile are analyzed. The results show that dry soil can dissipate excitation energy better than saturated soil; With the improvement of the properties of the core filling material, the amplitude of the reflected signal increases; The position of core filling height corresponds to the position of reverse reflection signal in the curve.