Optimization Of Urban Road Network System Layout Under Environmental Pollution Regulation

With the rapid development of economy and acceleration of urbanization process,the number of motor vehicle running in the urban road network is increasing rapidly,which not only brings great pressure to the existing traffic infrastructure of the city,but also brings serious threat to the environment and energy utilization.In this thesis,the process of pollution emission and dispersion are integrated to dynamically measure the emission and dispersion index of road mobile source pollutants,reveal and analyze their emission contribution and multi-coupling dispersion characteristics,and put forward the layout optimization method on flow from existing road network under the environmental pollution regulation and energy consumption optimal constraints so as to provide theoretical basis for formulating pollution control measures and optimizing the layout of urban road network.The main research works of this thesis are as follows:In order to solve the problem of accurate calculation for line source pollutant emission in a specific period of urban complex road network system,a new pollutant emission calculation model is proposed.Firstly,the road structure is abstracted,and the urban traffic network is treated as a collection of nodes and arcs to build a road network topology model;secondly,the flow behavior of vehicles in the road network is simulated by the flow of complex pipe network liquid,the calculation model of vehicle flow is built based on the analyzed flow law,and the solution algorithm-Neighborhood Adaptive Differential Evolution algorithm is given;then coupling emission factors to calculate the pollutant emission and the emission characteristics of line source contribution are revealed by using Arc GIS and other statistical tools.Finally,the model is verified by taking Xi’an road network as an example.Aiming at the problem of natural dispersion for air pollutant in urban road network under the coupling of multiple factors,a new multi-coupling dispersion model,which introduces the concept of object and function into the traditional Petri net,based on the theory of double branch fuzzy set,is defined,which comprehensively considers and analyzes the promotion and inhibition of pollutant dispersion.Firstly,DCCA method is used to describe the effect degree of each factor on pollutant dispersion and identify the polarity of its action;secondly,transition is used to represent dispersion triggering condition,object library is used to represent dispersion state of road network system,object attribute is used to represent dispersion index value,and object function is used to represent attribute updating behavior so as to directly reveal the logical causal relationship of multi-coupling dispersion process.The model updating rules and algorithm based on the two branch Object Petri net and the multi-coupling dispersion mechanism,are given.Finally,an abstract road network in Xi’an is taken as an example to analyze and discuss the model.Taking the existing road network structure as the research object,from the perspective of environmental pollution regulation and fuel consumption optimization,a multi-coupling double-layer optimization model considering multi vehicle structure is constructed to explore how to reasonably allocate the relatively infinite traffic flow under the existing road network,so as to achieve the purpose of reducing environmental pollution and fuel consumption at the same time.The upper layer of the model is pollution regulation and energy consumption optimal decision-making,and the lower layer is a series of planning models with equilibrium constraints,which are used to describe the reasonable distribution of road network flow under pollution and energy consumption constraints.At the same time,according to the double-layer model,an effective solution algorithm-Bimodal Learning Particle Swarm Optimization algorithm,is given.Finally,the Xi’an road network is taken as an example for analysis and optimization Research.Based on the complex pipe network fluid theory、nonlinear and double-layer planning、group intelligent optimization search algorithm、Both-Branch Object Petri net 、 time series correlation analysis and other methods,this thesis respectively constructs models such as pollutant emission measurement,multi-coupling dispersion and road network layout optimization,which provides the basis for the formulation of urban road network pollution traffic control measures and theoretical guidance for the optimal road network layout.