Research On Post-evaluation Of Pavement Performance Of Municipal Roads Based On FWD

With the development of economy and the expansion of the city,people undefineds demands on municipal roads have been raised continuously,and great achievements have been made in the construction of municipal roads in China.However,with the increase of traffic volume,municipal roads often appear different degrees of damage prematurely,and the damage of pavement structure performance makes the bearing capacity of roads.lower,which affects the use of roads.At present,the dynamic deflection basin is measured by FWD,and the dynamic modulus of road structure layer is calculated back to evaluate the pavement structure performance.It has become a hot spot of research.However,there are few studies on the post-evaluation of pavement structure performance through the dynamic modulus of pavement structure layer.First of all,a comprehensive introduction to the drop weight deflectometer is given,and the mechanical model,boundary conditions and programming of the Bisar software used in this paper to calculate the deflection value are described.Through Bisar software and control variable method,the influence law of modulus and thickness of pavement structure layer on deflection is analyzed,and the influence of compaction degree and mineral gradation of asphalt pavement on deflection is analyzed by field test.Secondly,the principle and method of dynamic modulus inverse calculation of road structure layer are discussed.The inverse calculation program of dynamic modulus of road structure layer is compiled by Visual Basic to analyze the influence of FWD measurement error,effective bit number of data,thickness of structure layer and different loads on dynamic modulus back calculation.Thirdly,aiming at the problems existing in the practical application of the current standard pavement strength evaluation method in China,a new post-evaluation system of pavement structure performance is constructed according to the dynamic modulus of back calculation.In this paper,the index of pavement structure performance(PSPI)is put forward to evaluate pavement structure performance.At the same time,according to the structural layer strength index(SLSIi)and PSPI formula to calculate the PSPI score.PSPI is used to quantitatively evaluate the pavement structure performance of municipal roads.A logical framework model for post-evaluation of pavement performance is constructed to evaluate the pavement performance qualitatively.Through the research in this paper,we can get various factors that affect the accuracy of deflection value and dynamic modulus of inverse calculation,and analyze the influence law of these factors,in order to improve the accuracy of dynamic modulus based on FWD inverse calculation.At the same time,through the new post-evaluation system of pavement structure performance of municipal road,the pavement structure performance of municipal road can be more accurately evaluated,and more accurate suggestions are provided for the maintenance and maintenance of municipal road.