新疆西准噶尔沙吉海地区地表形变时空特征分析及其环境意义

Analysis of the Spatial and Temporal Characteristics of Surface Deformation in the Shajihai Region of West Junggar, Xinjiang and Its Environmental Significance

煤矿地下开采形成的采空区对地表工程和周围环境造成严重的破坏,造成沙吉海矿区周围生态脆弱,草场面积缩减。长期废弃的矿井由于不清楚地下开采情况及范围,所以难以进行有效治理。通过长时间大范围的采空区形变特征监测,对于地质灾害预防和治理来说具有重要意义。基于2017年3月19日—2019年12月22日73幅覆盖沙吉海矿区的Sentinel-1A影像,采用差分干涉测量短基线集时序分析技术(small baseline subset interferometric synthetic aperture radar, SBAS-InSAR)获取时序地表残余变形,此外通过克里金插值法获取了整个研究区完整的形变信息,监测到研究区平均变形速率在-148.44~38.05 mm/a,最大累积形变量达-1 418.42 mm。分别得到废弃采空区和正在开采矿井工作面的形变特征,正在开采煤矿采空区呈漏斗形变形,废弃采空区沉降呈多点分散形,变化不均匀。经过对沙吉海矿区详细的野外调查,验证了SBAS-InSAR结果的可靠性。最后,结合野外验证结果分析了煤矿采空区围绕沉降中心呈漏斗形演化的过程。研究成果可为老旧采空区治理提供参考,对采空区变形预测具有指导意义。

The mining area formed by underground mining of coal mines has caused serious damage to surface works and the surrounding environment, resulting in ecological fragility and shrinkage of pasture areas around the Shajihai mine. Long-term abandoned mines are difficult to be effectively managed because the underground mining situation and its extent are not clear. Monitoring the deformation characteristics of the mining area through a long time and large scale is important for geological disaster prevention and management. Based on 73 Sentinel-1A images covering the Shajihai mine area from March 19, 2017 to December 22, 2019, small baseline subset synthetic aperture radar(SBAS-InSAR) was used to obtain temporal residual deformation. The average deformation rate of the study area is monitored to be-148.44~38.05 mm/a, and the maximum cumulative deformation is-1,418.42 mm. The deformation characteristics of the working face were obtained separately, and the deformation of the mining area in the mining mine was funnel-shaped, while the settlement of the abandoned mining area was multi-point dispersed and uneven. The reliability of SBAS-InSAR results was verified after a detailed field survey of the Shajihai mine area. Finally, the process of the coal mining void area evolving in a funnel shape around the subsidence center was analyzed in combination with the field verification results. The research results can provide reference for the management of old mining areas and guidance for the prediction of deformation of mining areas.