Research And Application Of Typical Hidden Diseases Of Asphalt Pavement Based On 3D Ground Penetrating Radar

Three-dimensional ground penetrating radar is developed on the basis of two-dimensional ground penetrating radar,and is gradually applied to the field of asphalt pavement detection,which has unique advantages compared with conventional detection of three-dimensional ground penetrating radar to achieve rapid and nondestructive detection of the interior of the structure.At present,there are the following problems in the detection of typical hidden diseases such as poor interlayer bonding and loose base layer of asphalt pavement using 3D ground penetrating radar: the specification only explains the parameters in the data acquisition software in the process of introducing the use of 3D ground penetrating radar,and does not give the recommended values of the sampling spacing,residence time and other parameters in the data acquisition software under different detection needs,which brings trouble to the actual detection work;The radar feature map of typical hidden diseases of asphalt pavement is greatly affected by factors such as disease moisture content,burial depth and size,and there is no literature to clarify the influence of these factors on radar feature map recognition.After obtaining the asphalt pavement radar detection data,only the asphalt pavement can be qualitatively evaluated,and it cannot be further used in the asphalt pavement structure damage evaluation.Based on the above problems,this thesis puts forward the following main research contents:(1)the optimal parameter settings under different requirements are determined by using the range analysis method through orthogonal experiments,taking sampling distance,residence time and speed as factors,and information entropy and clarity as evaluation indicators;(2)The influence of moisture content,buried depth,size and other factors on the radar characteristic map of typical hidden diseases of asphalt pavement was obtained by comparative analysis method by burying the physical model;(3)Using the entropy weight method to determine the weights of different diseases,the evaluation index of asphalt pavement base layer was proposed accordingly,and the asphalt pavement base layer evaluation method(RCI)was obtained by combining expert questionnaire survey and radar detection data by fitting,and the RCI was compared and analyzed with PSSI and PCI to propose an evaluation method for asphalt pavement structure damage based on RCI,PSSI and PCI,and corresponding maintenance measures were proposed.The main findings are as follows:(1)Parameter setting for the best effect of data acquisition software under different requirements: the recommended parameters for disease detection are sampling distance5 cm,residence time 2μs,and speed 10km/h;The task target is thickness detection,the recommended parameters are sampling distance of 8cm,residence time of 1μs,and speed does not exceed the maximum speed limit.(2)The influence of different factors on the characteristic map of disease radar is clarified,and the identification efficiency and accuracy of typical hidden diseases are improved: the radar feature map of interlayer combined with adverse diseases is a continuous image of light and dark staggered distortion,the radar feature map of loose diseases at the base level is a curved layered broken image with staggered light and dark,the higher the moisture content,the stronger the reflection of the disease radar feature map,the deeper the depth,the weaker the reflection of the disease radar feature map,the larger the size,the greater the strong reflection area on the cross-section,longitudinal section and horizontal section.(3)The entropy weight method was used to determine the weight of different diseases and the evaluation index of asphalt pavement base layer was proposed,and the asphalt pavement base layer evaluation method(RCI)was obtained by combining the expert questionnaire survey method with radar data,and the evaluation method of asphalt pavement structure damage condition was obtained by combining RCI,PSSI and PCI,and the qualitative radar detection data was quantitatively processed,and the evaluation results were more accurate and reasonable.(4)The asphalt pavement structure damage evaluation method is applied to the Angong Expressway for engineering verification and compared with the maintenance measures made by PCI,which proves that the asphalt pavement structure damage evaluation method is more accurate and reliable.