基于随机森林的川藏铁路沿线县域地质环境承载力评价

Evaluation of Geo-environmental Carrying Capacity of Counties along the Sichuan-Tibet Railway Based on Random Forest

川藏铁路对西藏社会经济发展具有十分重要的意义。为提升区域地质灾害防治能力与社会经济发展潜力,选取川藏铁路沿线33个县作为研究区,从地貌环境、地质环境、生态环境以及社会环境4个层面选取12个指标构建地质环境承载力评价指标体系,通过随机森林模型对各指标权重进行确定,利用地理信息系统(geographic information system, GIS)空间分析工具对川藏铁路沿线县域地质环境承载力进行评价。结果表明:川藏铁路沿线县域地质环境承载力总体表现良好,中等质量以上区域面积占比超半数,且质量较差区域主要集中于八宿县、察雅县一带,面积占比相对较小;川藏铁路沿线地质环境质量整体受区域地质背景即工程岩组与活动断层的影响较大,其次是归一化植被指数(normalized difference vegetation index, NDVI)为代表的生态环境质量。因此,建议在监测断层活动,控制沿线工程活动的基础上,重视沿线的生态保护与修复,以维护川藏铁路带来的发展“红利”,保证发展的可持续性。

Sichuan-Tibet Railway is of great importance to the social and economic development of Tibet. In order to enhance regional geological disaster prevention and control capabilities and assess socio-economic development potential. 33 counties along the Sichuan-Tibet Railway were selected as the study area, and 12 indicators were selected from four levels: geomorphological environment, geological environment, ecological environment and social environment to build the evaluation index system of geo-environmental carrying capacity, and the weights of each indicator were determined by random forest model, and geographic information system(GIS) spatial analysis was used to evaluate the geo-environmental carrying capacity of counties along the Sichuan-Tibet Railway. The results show that the geological environment quality of the counties along the Sichuan-Tibet Railway is generally good, and the area of medium quality or above accounts for more than half, and the area of poor quality is mainly concentrated in the area of Basu County and Chaya County, which accounts for a relatively small area. the overall geo-environmental carrying capacity along the Sichuan-Tibet Railway is influenced by the regional geological background, i.e., engineering rock groups and active faults, followed by the geo-environmental carrying capacity represented by normalized difference vegetation index(NDVI). Therefore, it is suggested that on the basis of monitoring fault activities and controlling engineering activities along the line, ecological protection and restoration along the line should be paid attention to in order to maintain the development “dividends” brought by the Sichuan-Tibet Railway and ensure the sustainability of development.