基于遥感分析的延安新区平山造城工程地面沉降及植被恢复特征研究

REMOTE SENSING ANALYSIS OF LAND SUBSIDENCE AND VEGETATION RESTORATION CHARACTERISTICS IN EXCAVATION AND FILLING AREAS OF MOUNTAIN REGION FOR URBAN EXTENSION IN YAN’AN

湿陷性黄土地区岩土工程往往涉及大量挖方填方工程,极易引发一系列的地面沉降和植被破坏问题。本文基于SBAS-InSAR技术结合遥感数据处理对延安新区平山造城工后地面沉降及植被恢复特征进行了分析。首先,通过目视解译及DEM提取,获取工程基本特征;随后,基于SBAS-InSAR技术对新区工后地面沉降进行探测;最后,利用遥感提取新区的NDVI时序数据。结果表明:(1)延安新区建筑工程建设滞后挖填方工程约2 a,填方区域沿着原始地形的沟谷展布,挖填方体最大厚度均超过90 m;(2)延安新区主要沉降区为填方区域,2017~2018年最大沉降速率达45 mm·a ^-1,主要建筑工程所处的挖方区无明显地面沉降,工程边坡大多处于稳定状态;(3)延安新区2013~2015年NDVI平均值增长230%,2015~2018年增长50%,植被恢复明显。延安新区平山造城工程的规划建设合理的规避了地面沉降及缓解了生态环境恶化,研究成果可为类似工程建设提供科学参考依据。

The excavation and filling works is frequently conducted in geotechnical engineering activities in collapsible loess area, which can easily lead to a series of geo-environmental problems such as land subsidence and vegetation damage. This paper examines the land subsidence and vegetation restoration characteristics of the mountain excavation and city construction project for Yan an New District. Firstly, the basic characteristics of the project are obtained using visual interpretation and DEM extraction method from the remote sensing images. Then, the ground settlement of the study area is detected based on SBAS techniques. Finally, the NDVI time series data are extracted by GF-1 remote sensing images. The conclusions can be found as follows. (1)The urban construction projects of Yan an New District are two years later after the large-scale land creation projects. The filling area is distributed along the valley of the original terrain. The maximum thickness of the excavation and filling square is more than 90m. (2)The main settlement area of Yan an New District is the filling area. The maximum subsidence rate is 45mm ·a ^-1 from 2017 to 2018. There is no obvious land subsidence in the excavation area where the main construction project is located. The man-made loess slopes are mostly in a stable state. (3)The average NDVI of Yan an New District increases 230% from 2013 to 2015, and increases 50% from 2015 to 2018 with apparent vegetation restoration. The planning and construction of the mountain excavation and city construction project in Yan an New District has reasonably avoided land subsidence and alleviated the deterioration of ecological environment. The results can provide scientific references for the similar projects.