兰州市城区沉降监测及其空间分异特性分析

Settlement monitoring and spatial differentiation analysis of Lanzhou City

利用时序InSAR的两种技术:PS-InSAR和SBAS-InSAR,对兰州主城区2017年2月至2019年6月共37景的降轨数据进行处理分析。根据实验共提取五处沉降区,经过对比,两种技术结果一致性较高,其形变范围大致相同,形变数值的相干性基本相近,时序上总体都呈现下降趋势,只存在少量偏差点,但SBAS-InSAR技术结果的形变及周围变化趋势更为明显且连续,数值变化相对平缓,精度较高。因此,以SBAS-InSAR形变结果为主,PS-InSAR形变结果为辅,由点及面,并结合地形、土质、植被覆盖、降水等因素,大致判定沉降原因与湿陷性黄土、水土流失和建筑物下沉有关。

Using two technologies of multi-temporal InSAR: PS-InSAR and SBAS-InSAR, the data of 37 descending scenes in the main urban area of Lanzhou from February 2017 to June 2019 are processed and analyzed. According to the experiment, a total of five settlement areas are extracted. After comparison, the results of the two technologies have high consistency, their deformation range is roughly the same, the coherence of deformation values is basically similar, and the overall time sequence shows a downward trend, with only a few deviation points. However, the deformation and surrounding change trend of SBAS-InSAR technology results are more obvious and continuous, the spatial deformation obtained is relatively gentle and the accuracy is high. Therefore, based on the deformation results of SBAS-InSAR and PS-InSAR and from point to surface, it is roughly determined that the settlement reason is related to collapsible loess, water and soil loss and building subsidence, combined with terrain, soil quality, vegetation cover, precipitation and other factors.