Study On Technical Condition Evaluation And Combination Forecast Method Of Reral Highway Asphalt Pavement In Liaoning Province

In recent years,Liaoning province rural highway construction and maintenance has been paid more and more attention.With the increase of service life,The pavement performance of rural roads has been decreasing year after year,which has seriously affected normal traffic of vehicles.In this paper,the technical condition evaluation and combination forecasting method of rural road asphalt pavement in Liaoning province are systematically studied.According to the environmental conditions in the province,this paper divides the performance of asphalt pavement in rural areas into five regions.This paper carries out a survey on the pavement structure,traffic volume and technical condition of the asphalt pavement of rural highway in each region,and field investigation on pavement disease of asphalt pavement of rural highway in key area is carried out.At a typical disease location,the core sample is drilled.By analyzing the damage degree of core sample and core wall,the failure of the surface layer corresponding to the base course failure is obtained,which lays a good foundation for the selection of the subsequent evaluation index.By analyzing the damage mechanism of all kinds of diseases,the rural road asphalt pavement in the province is divided into two categories:structural disease and non-structural disease,and the grading standard is determined according to the type and degree of disease.On the basis of this,the pavement damage index PCI and the base failure index BCI are selected as the evaluation indexes for the technical status of the rural highway asphalt pavement.A comprehensive evaluation model for asphalt pavement of rural highway in Liaoning province is established by using the trigonometric whitening weight function.The weight coefficient is determined by the combination of subjective weight and objective weight.The subjective weight is applied to expert opinion,the objective weight is applied to cosine method.According to this,the use of asphalt pavement and its ashes of many rural roads are calculated.The priority maintenance order of the asphalt pavement of various rural highways is determined.The service life of rural roads is relatively short.Usually,after four to five years,the performance of the road surface drops sharply.In addition,there is a little data of the historical investigation of asphalt pavement in rural roads,most of the rural road survey data is missing,or only a few years of historical data are available.Therefore,on the basis of the investigation on the actual situation of the road surface,the development rule of the road disease condition is summarized.The damage law of the asphalt pavement of the rural highway is divided into two types:the general destruction development model and the special destruction development model.According to the testing time of the road,the historical survey data of rural highway are divided into two results in March and September.The time-space method is used to expand the survey data.Through the comparison and analysis of the prediction model of common pavement performance.The BP neural network forecast model and the grey forecast GM(1,1)model are used in this paper.Under the general mode of destruction and development,the combination forecast principle is used to forecast the performance of the asphalt pavement in rural highway in Liaoning province.Finally,the combination forecast model of the asphalt pavement of the rural highway in Liaoning province is established.Through the analysis and demonstration of the application examples,it is concluded that the prediction results of the model have little error,The combined prediction model not only makes up the defects of the single model,but also makes the accuracy of the prediction result further improved.It has high practicability and feasibility.