堆积层滑坡多源遥感动态演变特征分析研究

Multi-source Remote Sensing Dynamic Deformation Monitoring of Accumulation Landslide

堆积层滑坡随库水位变动的响应规律是一个重要的研究课题,以往研究多采用地表位移实时监测数据耦合库水位数据开展分析,然而大多库岸边坡不具有开展专业监测的条件,这给滑坡的历史变形追溯带来一定困难。采用星载与机载平台多源立体化观测技术,从多角度、多尺度监测瀑布沟水电站红岩子滑坡从蓄水至今10余年的变形演化规律。综合研究表明,红岩子滑坡这类蓄水、降雨诱发的蠕滑-拉裂式滑坡具有典型的长期性、缓慢性与季节性特征;长时间序列合成孔径雷达能够较为准确地捕捉到这些特征信息;多期次光学遥感影像比对分析可较为直观地显现出滑坡不同位置宏观变形破坏特征的差异性,机载LiDAR获取的地表点云信息进行植被剔除后可准确识别出长期蠕滑的滑坡要素变化,在以上工作基础上结合地质条件与地表滑坡调查开展工程地质分析,最终研判出滑坡成因机制、变形模式与未来发展趋势。该研究可为类似工程案例研究提供科学的思路和方法,对蓄水诱发的缓慢蠕滑型滑坡的防治提供一定参考。

Objectives:The response law of ancient(old)landslides in the reservoir area is an important research topic.Previous research primarily analyzed real-time surface displacement and reservoir water level data.However,professional monitoring conditions are often lacking on most reservoir bank slopes.This complicates tracking the landslides historical deformation.Satellite and airborne remote sensing platforms enable multi-scale,long-term monitoring of landslide deformation and damage.Methods:This study employs multi-source three-dimensional observation technologies including aerial,space-based,and terrestrial platforms to monitor the deformation and evolution of the Pubugou Hydropower Stations Hongyanzi land‑slide over approximately 10 years. It utilizes unmanned aerial vehicle photography (optical imaging) andlight detection and ranging (LiDAR) for detailed topographic mapping and deformation analysis from 2009to 2020. Additionally, time-series interferometric synthetic aperture radar (InSAR) technology is used totrack long-term surface deformations from October 2014 to July 2020. Field investigations have identifiedtypical deformation and failure characteristics of the landslide, incorporating geological conditions and externalfactors such as rainfall and reservoir water levels to analyze causal mechanisms and dynamic trends. Re⁃sults: The irregularly semicircular Hongyanzi landslide spans 20-50 m in thickness, encompasses approximately15.53 million m³ in volume, and slides at an approximate bearing of 340°. Composed of quaternarypebbled stones, silty sand, and clay, the landslides bed slopes between 20° and 25°. Its lithology includesEmeishan Formation basalt and Yangxin Formation dolomite. Existing since 2006 or earlier, the landslidefeatures elements like walls and steps. LiDAR imagery from 2009 clearly delineates its boundaries, thoughit shows no new signs of deformation or failure. Following reservoir impoundment, the reactivated landslidedevelops new, widening cracks along its rear edge. Post-reactivation, the landslide predominantly undergosuniform deformation, with more significant movement at the trailing edge than the leading edge,without marked acceleration. Heavy rainfall is the most significant control factor, imparting stepwise deformationcharacteristics to the landslide. Conclusions: A comprehensive analysis of multi-source data revealsthat phenomena like the Hongyanzi landslide exhibit typical long-term, gradual, and seasonal movements.Long-term InSAR effectively captures these characteristics. Multi-stage optical remote sensing and surfacepoint cloud data from LiDAR, after vegetation removal, enable more intuitive comparisons of macroscopicdeformation across different landslide areas. Integrating this with geological assessments and field investigationsallows for detailed engineering analyses to ascertain the causes, patterns, and future trends of landslideactivity.