基于SBAS-InSAR的河口村水利工程形变监测与时空分析

Deformation monitoring and spatiotemporal analysis of Hekoucun water conservancy project using SBAS-InSAR

摘要

【目的】河口村水利工程具备防洪兴利等重要作用，其安全对当地社会经济发展意义重大，因此需要及时监测其形变态势，识别并规避安全隐患。【方法】相比传统形变监测方法，合成孔径雷达干涉测量技术(InSAR)具有全天时全天候、大范围高精度、高时空分辨率等优势。采用SBAS-InSAR技术提取了河口村水利工程研究区2017年10月—2022年12月的时序形变信息，基于水准实测数据验证了精度并与PS-InSAR对比，结合地理数据分析了水利工程的形变时空特性和影响因素。【结果】结果显示：SBAS方法的形变提取精度为5.21 mm, PSI精度为8.07 mm,且研究区的SBAS形变点密度为PSI的2.49倍。河口村库区形变速率为-8.6~3.2 mm/a,识别到了坝前广场和防汛仓库两处漏斗状沉降区，分别发生约45 mm和50 mm的沉降，其中防汛仓库在2021年7月大雨后沉降加剧。河口村大坝形变速率集中在-4~+2 mm/a之间，5年最大沉降量约15 mm,坝顶中央沉降最大，形变呈周期性波动。坝顶形变与降雨呈正相关，相关性均超过0.5;与水位呈负相关，相关性平均为-0.32。【结论】结果表明：SBAS方法相比PSI更能有效监测水利工程区的地表形变。坝前广场和防汛仓库的形变主要受降雨影响。大坝的整体形变特征为中央比两肩沉降大、坝顶比坝底沉降大，且水位越高，坝顶沉降越大。大坝形变呈周期性波动，且形变量较小，暂时不影响大坝的安全运行。研究结果可为河口村水利工程的安全运行提供科学支撑，并为其他水利工程的形变监测应用提供参考。

Abstract

[Objective] The Hekoucun water conservancy project plays a vital role in flood control and water resource utilization, and its safety is of great significance to the local socioeconomic development. Therefore, timely monitoring of its deformation trend is necessary to identify and mitigate potential safety hazards. [Methods] Compared with traditional deformation monitoring method, Interferometric Synthetic Aperture Radar(InSAR) offered advantages such as all-day and all-weather operation, large-scale high-precision coverage, and high spatiotemporal resolution. SBAS-InSAR was employed to extract time-series deformation information of the Hekoucun water conservancy project area from October 2017 to December 2022. The accuracy was validated using leveling measurements and compared with PS-InSAR result. The spatiotemporal characteristics and influencing factors of deformation were analyzed in combination with geographic data. [Results] The results showed that the deformation extraction accuracy of SBAS was 5.21 mm, while that of PSI was 8.07 mm. The density of SBAS deformation points in the study area was 2.49 times that of PSI. The deformation rate in the Hekoucun reservoir area ranged from-8.6 to 3.2 mm/a. Two funnel-shaped settlement zones were identified: the dam-front square(about 45 mm settlement) and the flood-control warehouse(about 50 mm settlement), with the latter showing accelerated settlement after heavy rainfall in July 2021. The deformation rate of the Hekoucun dam ranged from-4 to 2 mm/a, with the maximum settlement of about 15 mm over five years. The central part of the dam crest showed the greatest settlement, with periodic fluctuations. The dam crest deformation was positively correlated with rainfall(correlation coefficients all above 0.5) and negatively correlated with water level(average correlation of-0.32). [Conclusion] The results indicate that SBAS is more effective than PSI in monitoring surface deformation in water conservancy project areas. The deformation of the dam front square and flood-control warehouse is mainly influenced by rainfall. The overall deformation characteristics of the dam show greater settlement at the center than at the shoulders, and greater settlement at the dam crest than at the dam base. Additionally, higher water levels lead to increased settlement at the dam crest. Dam deformation shows periodic fluctuations of relatively small magnitude and currently does not compromise dam safety. The findings provide scientific support for the safe operation of the Hekoucun water conservancy project and serve as a reference for deformation monitoring in other water conservancy projects.

关键词

时序InSAR / 水利工程 / 土石坝 / 形变监测 / 时空特性 / 变形 / 沉降 / 降雨

Key words

time-series InSAR / water conservancy project / earth-rock dam / deformation monitoring / spatiotemporal characteristics / deformation / settlement / rainfall

基金资助

国家重点研发计划项目(2021YFB3900603)