| Large-scale railway construction under complex environmental conditions will inevitably caused environmental damage such as soil erosion,vegetation destruction and air pollution.The mountainous areas of Sichuan,which cover special environmentally sensitive areas,has complex topography,environmentally sensitive and fragile,and poor ecological restoration capabilities.Therefore,environmental issues must be considered when conducting ecological railway line selection in these areas,so as to guide railway planning and construction according in different environmental conditions.Based on the above problems,the main research contents as follows:Firstly,based on the development of Sichuan mountain railways,the background of rail transit construction in environmentally sensitive areas and combined with existing research results,the development of environmental sensitivity assessment and railway ecological route selection were summarized,the theory of environmental sensitivity assessment and he theory index monetizationen of vironmental impact assessment were introduced and the ecological route selection of mountain railways was discussed.Secondly,the interaction between engineering construction and the environment,the impact of engineering construction on the environment,and the constraints of environmental protection on engineering construction were analyzed.On this basis,an evaluation index system for rail transit projects in environmentally sensitive areas was constructed,and environmental sensitivity evaluation method was introduced.At the same time,interval analytic hierarchy process was used to calculate the evaluation index weight.Then,according to the environmental profile of the “Dujiangyan-Siguniangshan” rail transit project corridor,the environmental sensitivity of soil erosion,geological disasters,hydrological environment and special habitats were individually evaluated and comprehensive evaluated.The conclusion that the overall environmental sensitivity is moderately sensitive and soil erosion and special habitats have the greatest impact on the environment was obtained.Finally,evaluation index system for railway ecological route selection included engineering feasibility,natural environmental impact and social environmental impact was constructed based on the environmental sensitivity evaluation results of the " Dujiangyan-Siguniangshan" rail transit project and the environmental problems faced.Through the monetary calculation of environmental impact assessment indicators,the economic loss value of the project’s environmental impact was determined,and the local route plan was made based on the cloud model-projection-based railway ecological route selection decision. |
