基于SBAS-InSAR的关闭矿井地表形变规律研究

Research on surface deformation law of closed mines based on SBAS-InSAR

  • 摘要: 矿井关闭后,煤岩体在应力、地下水、氧气等多种因素的作用下发生风化劣化、强度降低,采动破裂岩体的应力和承载能力发生改变,易导致采空区地表发生二次形变。现有研究多是集中在矿区开采过程中的地表形变监测,而针对矿井关闭后的地表形变监测研究较少。为探明矿井关闭后地表的形变规律,利用2015-12-21—2019-12-24的62景Sentinel-1A影像,采用短基线集干涉测量(SBAS-InSAR)技术获取了徐州西部关闭矿井(包括庞庄矿、夹河矿和张小楼矿)4 a内时间序列的地表形变结果和形变规律。研究结果表明:3个矿区内地表最大沉降速率达-48 mm/a,4 a累计最大下沉178 mm;夹河矿地表呈现先下沉后抬升现象,而庞庄矿、张小楼矿地表持续下沉;4 a内3个矿区地表最大倾斜变形为1.70 mm/m,最大曲率变形为-0.039 mm/m2;通过插值统计计算得到庞庄矿、夹河矿和张小楼矿地表形变大于10 mm的形变面积分别为10.5,13.7,11.6 km2,且呈逐年上升趋势。

     

    Abstract: After the mine is closed, the coal and rock mass undergoes weathering degradation and strength reduction under the action of various factors such as stress, groundwater and oxygen. Moreover, the stress and bearing capacity of the mining fractured rock mass is changed, which is likely to cause secondary deformation of the surface of the goaf. Most of the existing researches focus on the monitoring of surface deformation during the mining process, while there are few researches on the monitoring of surface deformation after mine closure. To investigate the surface deformation law of closed mines, 62 Sentinel-1A images from 2015-12-21 to 2019-12-24 and small baseline subset-interferometric synthetic aperture radar (SBAS-InSAR) technology are used to obtain the surface deformation results and deformation laws of the time series within 4 years of the closed mines in western Xuzhou (including Pangzhuang Mine, Jiahe Mine and Zhangxiaolou Mine). The research results show that the maximum surface subsidence rate in three mines is -48 mm/a, and the cumulative maximum subsidence in 4 years is 178 mm. The surface of the Jiahe Mine shows subsidence followed by uplift, while the surfaces of the Pangzhuang Mine and Zhangxiaolou Mine continue to sink. The maximum surface deformation of three coal mines within 4 years is 1.70 mm/m, and the maximum curvature deformation is -0.039 mm/m2. Through interpolation statistical calculations, the surface deformations which are greater than 10 mm of Pangzhuang Mine, Jiahe Mine and Zhangxiaolou Mine are 10.5, 13.7 and 11.6 km2 respectively, and they are increasing year by year.

     

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