黄河流域中游采煤沉陷区地表形变InSAR与GNSS协同监测研究

    InSAR and GNSS collaborative monitoring of land surface deformation in the coal mining subsidence areas in the middle Yellow River Basin

    • 摘要: 针对黄河流域中游采煤沉陷区地表形变监测中单一技术手段难以兼顾大范围空间覆盖与高精度形变测量的局限性,本文以陕北黄土高原某大型煤矿为研究区,提出了一种InSAR与GNSS“先面后点”的递进式协同监测方法,旨在实现两种技术的优势互补,提升采煤沉陷区地表形变监测的时效性与精度。首先,利用SBAS-InSAR技术处理12景陆探一号(LT-1)L波段SAR数据(2023年12月—2024年12月),获取研究区大范围时序形变场,识别形变区域并分析其时空演化规律;其次,以InSAR圈定的关键形变区为靶区,基于20处GNSS监测站的高精度逐日监测数据,对地表形变阶段进行精细划分与定量分析,获取各阶段的累计下沉量、下沉速度及持续时间等关键参数。结果表明:①InSAR共筛查识别出A、B、C三个主要形变区,总面积约1.98 km2,形变区分布与同期开采工作面位置高度吻合,沉降中心随工作面推进呈规律性迁移;②基于GNSS逐日监测数据,地表形变全过程可划分为初始期(平均54 d)、活跃期(平均59 d,下沉量占总沉降量90%以上)和衰退期(平均262 d)三个阶段,形变过程平均持续367 d,最大累计下沉量达1 984.06 mm;③受煤层厚度、埋藏深度及煤柱保护效应等因素影响,西翼A形变区、B形变区活跃期形变剧烈且集中(下沉速度峰值分别达1 264.86 mm/月和1 134.51 mm/月),东翼C形变区活跃期延长但强度降低,且煤柱对采动应力具有显著的缓冲阻隔作用;④协同监测的数据时效性从传统水准测量的约20 d提升至小时级,形变区识别准确率较经验法提高约40%;大变形区垂直方向监测精度优于±5 mm,形变阶段划分误差≤±2 d,较传统经验公式估算精度提升1个数量级以上。研究表明:该“面状筛查+点状精测”的协同模式充分发挥了InSAR大范围连续监测与GNSS高精度点位实时监测的互补优势,显著提高了采煤沉陷区地表形变监测的时效性、准确性与精细化程度,可为黄河流域中游同类矿区灾害预警与生态修复提供可靠的技术支撑与科学依据。

       

      Abstract: To address the limitation of a single monitoring technique in balancing large-scale spatial coverage and high-precision deformation measurement for land surface deformation monitoring in coal mining subsidence areas of the middle Yellow River Basin, this paper proposes a progressive collaborative monitoring method of InSAR and GNSS following an “area first, point later” approach. A large coal mine on the Loess Plateau of Northern Shaanxi is selected as the study area, aiming to achieve complementary advantages of the two techniques and improve the timeliness and accuracy of deformation monitoring in coal mining subsidence areas. Firstly, SBAS-InSAR technology is applied to process 12 scenes of LuTan-1 (LT-1) L-band SAR data (from December 2023 to December 2024) to obtain a large-scale time-series deformation field, identify deformation zones, and analyze their spatiotemporal evolution patterns. Secondly, taking the key deformation zones delineated by InSAR as targets, high-precision daily monitoring data from 20 GNSS stations are used to finely classify the land surface deformation stages and quantitatively obtain key parameters including cumulative subsidence, subsidence rate, and duration of each stage. The results show that: ① three major deformation zones (A, B, and C) are identified by InSAR, with a total area of approximately 1.98 km2. The spatial distribution of these zones is highly consistent with the active mining faces during the monitoring period, and the subsidence centers migrate regularly with the advancement of mining faces. ② Based on GNSS daily monitoring data, the entire deformation process can be divided into three stages: the initial stage (averaging 54 days), the active stage (averaging 59 days, accounting for over 90% of the total subsidence), and the recession stage (averaging 262 days). The whole process lasts an average of 367 days, with a maximum cumulative subsidence of 1 984.06 mm. ③ Influenced by coal seam thickness, burial depth, and coal pillar protection effects, the active stage deformation in the western zones A and B is intense and concentrated (with peak subsidence rates of 1 264.86 mm/month and 1 134.51 mm/month, respectively), while the active stage in the eastern zone C is prolonged but with reduced intensity, and coal pillars exert a significant buffering and barrier effect on mining-induced stress. ④ The collaborative monitoring improves data timeliness from approximately 20 days (conventional leveling) to the hourly level, and increases the accuracy of deformation zone identification by about 40% compared to empirical methods. The vertical monitoring accuracy in large-gradient deformation areas is better than ±5 mm, and the error in deformation stage division is ≤±2 days, which is more than one order of magnitude better than that of empirical formula estimations. This study demonstrates that the collaborative mode of “areal scanning + point-based precise measuring” fully utilizes the complementary advantages of large-scale continuous monitoring by InSAR and high-precision real-time point monitoring by GNSS, significantly improving the timeliness, accuracy, and refinement of land surface deformation monitoring in coal mining subsidence areas. It provides reliable technical support and scientific basis for disaster early warning and ecological restoration in similar mining areas of the middle Yellow River Basin.

       

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