Study On The Application Technology Of Rayleigh Wave Detection For Roadbed Compactness Of Existing Highway

Subgrade is an important structure of highway. Compactness is one of the key index of subgrade condition,and inadequate compactness leads to roadbed defects. According to compactness subgrade resilient modulus which is the evaluation of pavement performance and pavement thickness design can be calculated. Therefore, detection of existing highway roadbed compactness is of significance. Rayleigh wave method is an ideal but immature nondestructive detection method for existing highway subgrade compactness. So we should research the application technology of Rayleigh wave method,which is useded to detect existing highway subgrade compactness. The main points were summarized as follows:(1)The existing Rayleigh wave detector grounding device was reformed, through experimental analysis, we can conclude that the reformed Rayleigh wave detector grounding device is completely applicable to the testing for existing freeway.(2)The new automatic Rayleigh wave excitation instrument was invented, which improved efficiency and controllability of Rayleigh wave excitation, through experimental analysis, we can draw a conclution that the new automatic Rayleigh wave excitation instrument is better than traditional artificial Rayleigh wave excitation method.(3)The rapid Rayleigh wave detection vehicle was invented,which has changed the traditional way of working,and made the detection automatic and faster. Through experimental analysis, proved that the rapid Rayleigh wave detection vehicle is more befitting for existing freeway than traditional detective method.(4)A new data preprocessing method of 1D denoising, automatic gain and resonance suppression was put forward, which improved the signal to noise ratio of Rayleigh wave date for existing highway.(5)A new method of fitting the curve of relationship between velocity of Rayleigh wave and the compactness was put forward, Through the test, we can conclude that the detective results of new fitting method is more accurate than traditional method.(6) The modified Rayleigh wave device and the improved data processing methods were applied to LeiYi Expressway overhaul project,the test prove that the modified Rayleigh wave device and improved detection method is feasible for existing highway, the dates of Rayleigh wave detection provided effective basis for the highway subgrade condition evaluation.