Numerical Simulation And Emulation Of Elastic Wave Transmission In Pile

At the beginning of this dissertation, the theory of low strain pile detection has been introduced, as well as the development of the elastic wave solution using the method of finite element and finite difference. On the basis of the deep research on the nature of elastic wave transmission in infinite domains and the effects of different boundary conditions, we establish the 3-D pile-soil math model of elastic wave transmission. Later, we solve the model and do emulation with finite element method. In the model, various defect parameters and signal receive points have been set to analysis the vibration characters of the elastic wave signal samples in different situations. The primary works of this dissertation are listed below:1. The theory of elastic wave transmission in pile-soil has been introduced, and the three dimensional elastic wave transmission math model in pile-soil has been established. Putting several geometries into the pile-soil model including cylinder, hemispheroid and sphericity; setting reasonable boundary conditions such as free surface, medium interface, hole and artificial boundary;2. The finite element theory variation is studied in the dissertation of the transmission model and the solving detailed approaches and implementation is given out; various boundary treatments are discussed, and finally the stimulant signal samples are obtained;3. Different defect parameters and signal receiving nodes have been set up to obtain signal samples with different parameters and analyze their libration characters; signal samples are compared to analyze the influence of the signal libration characters with various defect parameters and receiving nodes.4. On the situation both computing time and calculation accuracy, the influence about simulation data is discussed under different sizes of model. And the optimum range of geometry parameters of the model is obtained at last.The research achievements in this dissertation have a referenced significance in the field testing signals analysis of pile stress wave in certain degree, also have some promoting for the simulation development of pile stress wave testing.