| With the rapid development of economy and the continuous improvement of people’s demand for traffic, our country has achieved great success in highway construction. However, the rapid growth in traffic, particularly heavy load, overload vehicle growth, with the comprehensive influence of construction factors and the external environment, lead to pavement structure prematurely have different degrees of damage. Structural damage will reduce the overall bearing capacity of pavement structure. Currently, semi-rigid base asphalt pavement used in China generally, and by falling weight deflectometer (FWD) measured pavement dynamic deflection basin information and inverse pavement layer modulus to evaluate pavement performance, it has become a national expert a hot research topic. Nowadays, there is no FWD deflection testing and evaluation method for semi-rigid base asphalt pavement structure. Therefore, on the basis of the date of FWD, constructional evaluation system was built in this dissertation, which is fit for Semi-rigid base asphalt pavement.In this paper, the dynamic deflection basin of semi-rigid base asphalt pavement is detected by using FWD. Based on inverse principle and method of semi-rigid base asphalt pavement layer modulus, relied on the test road of G206 Lai Zhou section、G35 highway De Shang section、S250 provincial road Fei Liang line, carried out the research of semi-rigid base asphalt pavement performance evaluation method based on the FWD.First, the paper discuss parameters and characteristics of the deflection basin. The influences of the structure% material environment and other factors for the parameters of the deflection basin is studied. Using controlling the variable method, based on the theory of layered elastic system, the influences of structure combination type, temperature parameter, humidity parameter, structure layer modulus parameter and the connection state of the layer on deflection basin was analyzed by using Bisar software.Secondly, Fully discusses the pavement layer moduli backcalculation principle and backcalculation method, and compared the backcalculation procedures, combined with the deflection basin factors conclusions, adopting SIDMOD program, analyzed to a large number of moduli backcalculations. The influences of load, pavement structure type, structure layer thickness, structure layer combination, sensor arrangement mode, and inter layer connection states on the backcalculation modulus are analyzed. Then, take subgrade modulus for example, quantitative analysis of modular inverse calculation method. Based on the data obtained FWD detected, statistics directly deflection index, calculated deflection basin area, and inverse soil resilient modulus. SPSS software was used to analyze the correlation of subgrade modulus results backcalculation and among the indexes. Results are compared with SIDMOD inverse results, DCP test results and PFWD calculations so that check the accuracy of SIDMOD backcalculated results. In order to study application of FWD in practical engineering, based on the road survey, according to FWD data, the deflection basin parameters are calculated and analyzed to evaluate the road pavement performance. Combining pavement core drilling and 3D Ground Penetrating Radar detection, comprehensive evaluation of pavement performance are made. Finally, based on the research results in this paper, formulated a guide for FWD detection technology of semi-rigid base asphalt Pavement. Through this study, a variety of factors in deflection value and inverse calculation modulus can be obtained, quantitative analyse the impact of various factors, to improve the detection accuracy and modulus reverse calculation accuracy of FWD have a role. And guide the engineering application methods, Standardize the operation of FWD, provide the basis for the semi-rigid base asphalt pavement maintenance and repair. |
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