Design Of Maximum Grade Of Ramp For Highway Interchange Facing Speed Renovation Construction

With the development of social economy,the main highways that existed in the periphery of the city were gradually surrounded by urban development.The short-distance traffic gradually invaded the main roads,and the trucks entering the urban trunks also restricted the rapid transit of passenger cars inside the city.Such arterial highways and urban expressways not only undertake the function of transit traffic,but also need to meet the needs of rapid access within the city,but they cannot afford their functions under the influence of mixed passenger and freight traffic and morning and evening commuting peaks.Therefore,such arterial highways and urban expressways in urbanized areas urgently need to be rapidly reconstructed.The traffic characteristics of urbanized areas are studied through the investigation of traffic conditions in urbanized areas and related data.As a result,the mixed passenger and freight traffic in urbanized areas is serious,the traffic volume of unevenness is large,and the speed of passenger cars is limited.The level of road service is low.The selection of longitudinal slope indicators are forced on exploring for highway rapid construction interchanges,and a highway rapid construction interchange curve model is built on VISSIM software.In order to ensure that the model adapts to the traffic characteristics of urbanized areas,Volkswagen and FAW Jiefang J6 P tractor CA4250P66K25T1A1E5 were selected as the leading models of simulation,and the model parameters were calibrated,and the actual traffic volume of a certain intersection in Nanjing was used for multiple simulation tests.Secondly,the rapid highway interchange ramp model was established.Through the adjustment of the number of people-carriers and vans,the mixed rate of carts,and other factors,the recommended value of the rapid road ramp gradient at different design speeds is obtained according to the control variable method.The difference in road specifications is that the maximum longitudinal slope is recommended to be 3.5% and 4.5% at the design speed of 70km/h and 50km/h.Finally,the evaluation system of the interchange is established,to evaluate the vertical slope setting which breakthroughs the standards.The average delay and travel time are selected as the evaluation indicators.The result is that the recommended value of the maximum longitudinal slope of the highway interchange based on the mixed rate of carts is better compared with the current highway regulations.And the rapid transformation of the interchange is evaluated for Nanjing Shuanglong Street Interchange.