Abstract

The coalfield in the northwest suburbs of Xuzhou has suffered from extensive land subsidence; however, the temporal nonlinearity and corresponding spatial variation of its surface deformation has not been adequately explored. This study revealed complex surface deformation of the study area from 2015 to 2020 using time series InSAR. A general trend from sharp subsidence to moderated subsidence or even uplift is observed. Three main characteristic types of deformation time series, namely “Subsidence (S)”, “Subsidence–Uplift (S-U)” and “Subsidence–Uplift–Subsidence (S-U-S)”, were detected. Generally, mining activities control the fundamental constraining factors for the surface deformation. Mine closures affect the date of reversal from subsidence to uplift, or in other places the return to subsidence after uplift. Higher deformation rates in preceding sections of the deformation time series are generally correlated with later reversals of deformation trend and higher deformation rates of the succeeding sections of the time series. However, universally applicable spatial and temporal patterns of deformation were not detected, suggesting that surface deformation in the study area is a very complex process. Detailed process and mechanism analysis of surface deformation in the study area should focus on specific mines and pay particular attentions on dewatering and subsequent flooding of mines.

摘要

徐州西北郊煤田发生大面积地面沉降；然而，其表面变形的时间非线性和相应的空间变化尚未得到充分探索。本研究利用时间序列 InSAR 揭示了研究区 2015 年至 2020 年的复杂地表变形。观察到从急剧下沉到缓和下沉甚至抬升的总体趋势。检测到三种主要的变形时间序列特征类型，即“沉降（S）”、“沉降-隆起（SU）”和“沉降-隆起-沉降（SUS）”。一般来说，采矿活动控制着地表变形的基本约束因素。矿山关闭影响从沉降到隆起逆转的日期，或在其他地方隆起后恢复沉降的日期。变形时间序列前面部分的较高变形率通常与变形趋势的后期逆转和时间序列后续部分的较高变形率相关。然而，没有检测到普遍适用的时空变形模式，这表明研究区的地表变形是一个非常复杂的过程。研究区地表变形的详细过程和机理分析应以具体矿山为重点，重点关注矿山的脱水和后续淹水。没有检测到普遍适用的时空变形模式，这表明研究区的地表变形是一个非常复杂的过程。研究区地表变形的详细过程和机理分析应以具体矿山为重点，重点关注矿山的脱水和后续淹水。没有检测到普遍适用的时空变形模式，这表明研究区的地表变形是一个非常复杂的过程。研究区地表变形的详细过程和机理分析应以具体矿山为重点，重点关注矿山的脱水和后续淹水。