Reseach On The Optimal Methods Of Railway Oriented Environment In Ecologically Sensitive Areas

As an important transportation infrastructure,the construction of railway projects is often accompanied by social progress,the rapid economic development of the region under its jurisdiction and the improvement of people’s living standards.To a certain extent,it will also exacerbate the pressure on resources and environment,and have a negative impact on the surrounding environment.When railway projects inevitably cross the ecologically sensitive areas,due to the fragile environment within the region,in addition to considering the positive social benefits brought by the railway,we should also focus on its impact on the natural environment and the ecological environment,and pay attention to the coordinated development of the area under the jurisdiction.In this paper,combined with the characteristics of the ecologically sensitive areas,based on the concept of environmental route selection,the optimal method of environmental route selection in ecologically sensitive areas is researched.Combined with the engineering example of Lazi-Jilong section of Xinzang Railway,it is verified which has certain reference significance for the optimal method of environmental route selection in ecologically sensitive areas.The main research work and results of this paper are as follows:Firstly,the basic concepts such as the connotation,definition scope and classification method of the ecologically sensitive areas are introduced,and the problems that may be faced on the construction of railway projects within the scope of ecologically sensitive areas are analyzed.In order to solve these problems,the concept and characteristics of environmental route selection is introduced,and the general principles and specific operation steps are summarized.The target of optimal method in Ecologically Sensitive Areas is definite and provides a theoretical basis for the construction of index system in subsequent chapters.Secondly,based on the concepts and requirements of EIA,the impacts of railway construction on social environment,natural environment and ecological environment are analyzed.Combined with the existing research,the indicators which reflect the typical characteristics of railway environmental route selection in ecologically sensitive areas are selected,and the index system with some Principles and Methods is built up.The subjective weight is calculated by the weighted least-square method,and the objective weight is calculated by the fuzzy entropy method.The combination weight is calculated by the chi-square distance.Thirdly,according to the advantages,disadvantages and applicable conditions of some optimal methods,the TOPSIS model is optimized and the improved TOPSIS model is constructed based on the GRA.Then the optimal method of environmental route selection in ecologically sensitive areas is studied.The feasibility of this method is verified by the engineering case of Lazi-Jilong section of Xinzang Railway which is crossing two national nature reserves.According to the relative closeness value and the recommendation of decision-making units,the optimal scheme is selected.Finally,combined with the characteristics of the ecologically sensitive area,the influences of the construction of railway projects on the natural environment and ecological environment are analyzed emphatically.In view of these adverse effects,some corresponding environmental protection measures which strengthen the ecological protection and pollution prevention are put forward to control the environmental influence of the project in ecologically sensitive area(this line involves national nature reserves).