Analysis On Ground Vibration By Pile Driving

In the modern urban construction, pile foundation has become a common foundation style because of the development of tall buildings. The prefab pile has a widely use because of its good quality, stable and high bearing capacity, and good construction efficiency etc. Based on the different driving methods, the prefab piles can be defined as driven piles and jacked piles. In installation, the jacked piles have no vibration, no noise and have inconspicuous effect on neighborhood surroundings, but the cost is quite higher than driven piles'. So the use of driven piles is inevitable, but in installation, it will produce rather big noise and violent vibration. Along with reconstruction and expansion of modern cities, the effect on buildings around by pile driving vibration has aroused the attention of people.In order to study ground vibrations due to pile driving, one dimensional stress wave theory was used to establish the model of elastic pile with invariable sections in the visco-elastic layered soils. The semi-analytical solution of the displacement along the pile shaft was derived. Taking advantage of the interaction between pile and soil, the force that the soil was subjected from pile driving was simplified to the contact surface of the layered soils. Based on complex damping theory and Navier's equation, the displacement of soil under any load was calculated using multi-layer method, the velocity and acceleration was deduced and spectrum was analyzed. The attenuation characteristics of ground vibrations caused by pile driving were proposed. The feasibility of this model was assured by comparing the theoretical analysis and field test data.The main contents of this paper can be summarized as follows:1. Establishing the mechanic model of elastic pile, on the basis of this model, the moving equation of the pile was established, the semi-analytical solution of vertical vibration on pile was derived under any load on the top of pile.2. Taking advantage of the interaction between pile and soil, the force that the soil was subjected from pile driving was simplified to the contact surface of the layered soils. Based on complex damping theory and Navier's equation, the displacement of soil under any load was calculated using multi-layer method, the velocity and acceleration was deduced.3. By use of Matlab, the corresponding program was programmed, and the theoretical analysis and field test data was compared.Finally, the problems which need further study was provided.