复杂植被山区滑坡蠕变与植被覆盖度关系研究

Study on the relationship between landslide creep and vegetation cover in mountainous areas with complex vegetation

针对目前复杂植被山区滑坡蠕变监测受植被覆盖影响较大、不同植被覆盖度下滑坡蠕变关系研究缺乏等问题,该文联合Sentinel-1和ALOS PALSAR-2数据集,分别利用SBAS-InSAR和D-InSAR两轨差分技术,获取研究区2019年7月—2020年8月的雷达视线向形变时间序列,分析了复杂植被山区滑坡蠕变与植被覆盖度的内在关系。结果表明:(1)不同植被覆盖度等级对平寨水库库岸山区滑坡蠕变的影响具有显著差异,在低、中高和高植被覆盖度等级时诱发坡体沉降,在中植被覆盖度等级时抑制滑坡蠕变;(2)平寨水库库岸山区的滑坡蠕变体主要集中在库区NW-SE方向,分布与三岔河流域的流向相近;(3)联合多源数据对复杂植被山区滑坡蠕变进行组合探测能够有效克服时间、空间去相干影响,使滑坡蠕变体监测结果更为可靠。研究结果揭示了滑坡蠕变与植被覆盖的内在联系,可以为区域尺度防灾减灾事业提供科学支持。

In response to the problem that the monitoring of landslide creep in complex vegetated mountainous areas was greatly influenced by vegetation cover and the lack of research on the relationship between landslide creep under different vegetation cover,this paper combined the Sentinel-1 and ALOS PALSAR-2 datasets and used the SBAS-InSAR and D-InSAR two-track differencing techniques to obtain the time series of radar line-of-sight deformation in the study area from July 2019 to August 2020,respectively.The time series of radar line-of-sight deformation was used to analyze the intrinsic relationship between landslide creep and vegetation cover in mountainous areas with complex vegetation.The results showed that:(1)the influence of different vegetation cover classes on landslide creep in the reservoir bank mountains of Pingzhai Reservoir was significantly different,inducing slope subsidence at low,medium-high and high vegetation cover classes and suppressing landslide creep at medium vegetation cover classes.(2)landslide creep in the reservoir bank mountains of Pingzhai Reservoir was mainly concentrated in the NW-SE direction of the reservoir area,and the distribution was similar to the flow direction of the Sancha River basin.(3)Combined detection of landslide creep in complex vegetated mountainous areas with multiple sources of data could effectively overcome the effects of temporal and spatial decoherence and make the monitoring results of landslide creep bodies more reliable.The results of the study revealed the intrinsic link between landslide creep and vegetation cover,which could provide scientific support for disaster prevention and mitigation on a regional scale.