Research On Ecological Environmental Impact Assessment Of Railway Bridge Construction Period In Northwest China

By 2019,China’s railway operating mileage has reached more than 131,000 kilometers,the total mileage of high-speed railway has accounted for 2 / third of the world,and the construction of the "eight vertical and eight horizontal" high-speed railway network has been in full swing.The rapid development of railway has brought China’s economic take-off in China,but also has a certain impact on the ecological environment.Due to the long railway construction cycle,the drought,cold and dry areas,large sand,serious desert and fragile ecology,under such ecological conditions,damage to the ecological environment is inevitable.In the whole railway construction,the bridge construction accounts for more than 70%,so it is very necessary to establish the ecological environmental impact assessment of the railway bridge construction period in the northwest cold and dry areas.In general,after learning the theory of ecological system and a large number of papers on the ecological and environmental impact assessment,the geographical characteristics of railway bridge construction for example,and basically the same with the actual situation.(1)This paper follows the theory of ecosystem,The principle of establishing the index system is clarified,The impact of the railway bridge construction period on the ecological environment is analyzed,After learning the relevant ecological and environmental impact assessment methods,Combining the landscape pattern analysis method and the system analysis method,To evaluate the ecological environmental impact of railway bridge construction period in northwest China,Reasonable application of GIS software and Fragstats4.2 landscape analysis software to output relevant data and combine with engineering environment evaluation,Feasibility study report-related information,The way of combining quantitative data with qualitative data,The more systematic evaluation of the ecological environment.(2)This paper uses the DSR model,Establish the ecological environmental impact assessment index system of northwest railway bridge construction period from the three directions of driving force,status and response,The indicators are divided into three categories: driving force indicators,status indicators and response indicators;Primary indicators include water quality pollution,soil erosion,solid waste,gas pollution,noise pollution,vegetation destruction,sensitivity factors,landscape pattern index,biodiversity,Preventive measures and recovery 11 primary indicators,The secondary indicators include 25 indicators,such as water source pollution index,groundwater pollution index,soil loss rate,excavation utilization rate,solid waste production,harmful gases,dust,noise,biological loss,vegetation coverage,desertification sensitivity index,and secondary saline and alkalinity sensitivity index.(3)We studied each index separately and found the most suitable quantitative method for this paper.After exploring the evaluation standards of domestic and foreign documents,the evaluation standard of the ecological environmental evaluation indicators of railway bridge construction period in Northwest cold and dry areas was determined.(4)After briefly summarizing and analyzing the common empowerment methods,the evaluation index is endowed by the standard difference to correct G1 method,and using the cloud model to calculate the membership of the five levels,and determine the evaluation level in accordance with the principle of maximum certainty.(5)Taking the Dabancheng Wetland Bridge of Xinjiang section of Lanxin Railway as an example,using the evaluation index system and cloud model established by the DSR model,the results are generally consistent with the actual situation,and verify the rationality of the index system and evaluation model.And the corresponding recovery measures,put forward to minimize the impact of the construction on the ecological environment.