| Road construction and maintenance work is closely related to road detection technology.Due to its low efficiency,poor representativeness,and destructive damage to the road structure,the traditional road inspection technology means of core drilling is difficult to meet the requirements of modern road construction.In recent years,with the development of science and technology,road non-destructive testing technology represented by ground penetrating radar technology and falling weight deflectometer technology has been widely used in asphalt pavement quality testing.However,in practical application,there are shortcomings in using only one non-destructive testing equipment for pavement inspection.Although the ground penetrating radar technology can analyze the characteristics of the internal diseases of the asphalt pavement structural layer,it cannot analyze the diseases from the perspective of the bearing capacity of the structural layer.The degree of development of the asphalt pavement can be clearly judged;although the technology of the drop-weight deflection instrument can accurately evaluate the bearing capacity of the asphalt pavement structural layer,it cannot accurately judge the internal disease type and size of the asphalt pavement.In this regard,this paper focuses on the comprehensive application of nondestructive testing methods for road surfaces,and combines the advantages of two types of non-destructive testing: ground penetrating radar detection and falling weight deflectometer detection.The forward modeling technology analyzes the characteristics of the radar spectrum of typical diseases and establishes the correlation between the electromagnetic wave voltage signal and the disease size;the FWD forward modeling technology is used to simulate the deflection response of the typical disease site of the asphalt pavement,and the appropriate deflection basin parameters are selected.The index analysis was carried out,and an inverse calculation method of electromagnetic wave voltage signal,deflection parameters and disease size was developed.The main research results are as follows:In this regard,this paper focuses on the comprehensive application of non-destructive testing methods for pavement,and combines the advantages of two kinds of non-destructive testing,ground penetrating radar detection and falling weight deflectometer detection,to realize the complementary advantages of the two detection methods,and establish a comprehensive consideration of the two detection methods,establish a structural performance evaluation method based on joint detection.The main research results of the new index of structural performance evaluation are as follows:(1)A typical disease radar map of Beijing-Hong Kong-Macao Expressway was established.Through the combined use of ground penetrating radar forward modeling technology and ground penetrating radar field detection technology,the image characteristics and data characteristics of different types of diseases are compared,and the typical disease radar maps of single surface cracks,hidden cracks and water-bearing voids are established.(2)Correlation between typical lesion size and electromagnetic wave voltage signal determined.By setting the crack diseases of different depths and widths,the correlation between the crack diseases of different depths and widths and the electromagnetic wave voltage signal is established,and the mutual calculation between the crack disease size and the voltage signal is realized;disease,establish the correlation between cavity disease and electromagnetic wave voltage signal under different moisture content,and realize mutual calculation between cavity disease size and voltage signal.(3)Analyzed the deflection characteristics of different characteristic sections of Beijing-Hong Kong-Macao Expressway and the deflection characteristics of diseased parts.Through FWD on-site data collection,the deflection characteristics of different maintenance sections and different lane types are determined,that is,under different lanes in the same maintenance section,the deflection value of the driving lane is greater than the deflection value at the shoulder;under different maintenance sections of the same lane,The deflection value of the road section with long maintenance time is greater than that of the short maintenance time.According to the location and type of the disease determined by GPR,the law of deflection value at cracks,looseness and subsidence disease is analyzed and the corresponding elastic modulus is calculated.(4)Based on the combined detection of GPR and FWD,the inverse relationship between electromagnetic wave voltage signal,deflection index and disease size was determined.By analyzing the deflection response and modulus of resilience at different crack sizes,a mathematical regression method was used to correlate the crack size with the deflection value and modulus of resilience,and the relationship between the depth and width of cracks and the modulus of resilience was established.(5)Based on FWD forward modeling technology,the inverse calculation relationship between multiple indicators is verified and the inverse calculation accuracy is further improved.By selecting appropriate deflection basin parameters,calculating and analyzing the deflection value after numerical simulation,the corresponding relationship between different fracture sizes and deflection basin parameters is established,and multiple sets of formulas for mutual inverse calculation are established,which improves the relationship between fracture size and deflection.Inverse calculation accuracy of sink value.(6)A method for evaluating the structural performance of asphalt pavement based on the joint detection of GPR and FWD is established.Based on the above conclusions,the disease type and size of joint detection are determined,the data of Beijing-Hong Kong-Macao Expressway is collected and analyzed,and the structural performance of asphalt pavement is evaluated. |
