The Study On Application Of Elastic Wave Reflecting Technique On Non-Damaging Inspection Of Highway Surface Quality

In this paper, on the basis of the properties of elastic-waves propagation, the reflectivity technique and the boundary element method (BEM) technique were presented to study non-damaging inspection to the highway-surface quality. Functions of fixate point source and model of highway-surface were provided. The formula for reflectance and displacement on free surface were obtained, based on the reflectivity theory. Numerical simulation for seismic wave propagating in each of highway-surface concrete medium has been performed. From the simulation results, inverted deduction was observed for compaction degree, thickness and crack in highway-surface. The main results could be summarized as:1. The reflectivity method can be used to simulate the elastic-waves propagation in stratified homogeneous isotropic media of highway-surface. By obtaining the arrival time and velocity of reflected wave, the elastic-wave propagating distance can be calculated. The thickness of each layer of the highway was then deduced conjunction with the using of other material parameter.2. To measure the thickness of highway-surface and the dilapidation of concrete material more accurately, incident wave with high frequency was normally used. However, by analyzing frequency range for low frequency, it is possible to calculated material parameter of highway-surface.3. To provide theory foundation for inverted deduction work, numerical simulation for propagating in highway-surface with exceptional block and inanition and crack has been performed. The numerical simulation results show that the BEM is an effective method for the elastic-waves propagating in highway-surface concrete medium.