利用小基线集InSAR技术的延安新区地面抬升监测与分析

Land Uplift Monitoring and Analysis in Yan'an New District Based on SBAS-InSAR Technology

  • 摘要: 延安新区的平山造城是黄土高原地区规模最大的造地工程之一,大规模的山体开挖导致了广泛的地面抬升现象。同时,挖方区作为新区城市化建设的主要场地,地面抬升严重影响了新区城市的持续发展。利用小基线集合成孔径雷达干涉测量(small baseline subset interferometric synthetic aperture radar,SBAS-InSAR)技术对覆盖新区2016-05—2019-10期间的升轨Sentinel-1A数据进行处理,获取了新区工后长期地面形变信息,揭示了地面抬升空间分布规律及其形变演化特征,并对地面抬升成因进行了详细分析。结果表明,新区工后地面抬升显著,主要分布在对人类工程活动影响最大的挖方区,最大抬升速率达24.8 mm/a;地面抬升变形在工后初期发展较快,随时间发展有趋缓并稳定的趋势。山体快速开挖引起的卸荷回弹变形是地面抬升的主要内在因素,而地面抬升的分布及大小是由挖方工程范围、挖方厚度、建筑荷载等外在因素综合作用的结果。

     

    Abstract:
      Objectives  The mountain excavation and city construction in Yan'an New District is one of the largest land-creation projects in the Loess Plateau. Large-scale mountain excavation has induced extensive land uplift in the region. At the same time, the excavation area is the main site for the urbanization of the new district, and the land uplift has seriously affected the sustainable development of urbanization in the new district.
      Methods  In this study, the small baseline subset synthetic aperture radar interferometry (SBAS-InSAR) technology was utilized to process the ascending Sentinel-1A data stacks covering the new district from May 2016 to October 2019 to retrieve long-term ground deformation information after construction. The spatial pattern of ground uplift and its time deformation evolution characteristics was revealed, and the causes of land uplift were further quantitatively analyzed in detail.
      Results  The results show that significant land uplift of the new district after construction is mainly distributed in the excavation area that has the greatest impact on human engineering activities, with a maximum uplift rate of 24.8 mm/a. The ground lifting deformation develops rapidly in the early post-construction period, and it tends to slow down and stabilize over time.
      Conclusions  The unloading rebound deformation caused by the rapid mountain excavation is the main internal factor causing land uplifting, and the distribution and magnitude of the land uplifting are the result of the combined effects of external factors such as excavation engineering, excavation thickness, and building load.

     

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