基于机载LiDAR技术的泥石流物源侵蚀量定量评价研究

泥石流物源是形成泥石流的三大基本条件之一，物源侵蚀堆积变化量则是衡量泥石流规模和频率的重要指标，然而目前采用常规技术手段仍难以实现对物源侵蚀堆积变化的定量研究。针对这一问题，本文以西昌市邛海水厂后山冲沟泥石流为例，采用机载LiDAR技术建立了该流域雨季前后的高精度数字高程模型（DEM），并基于此开展了泥石流物源侵蚀量定量评价研究。结果表明：邛海水厂后山冲沟流域总体过火面积达65%，流域内主要发育坡面堆积物源、崩滑堆积物源以及沟道堆积物源；两期次高精度DEM数据差分叠加可实现泥石流物源侵蚀量的估算，该沟雨季前后泥石流物源侵蚀减少量为12209 m³，物源侵蚀变化呈分布区域广、数量多、散状发育的特点；泥石流物源的启动以坡面堆积物源侵蚀为主，侵蚀厚度多在0.5 m以内；邛海水厂后山冲沟泥石流在今后一段时间内将以高频泥石流为主。

Quantitative evaluation of debris flow provenance erosion based on Airborne Lidar Technology

The material source is one of the three basic conditions for the formation of debris flow,and the change in erosion accumulation of the material source is an important index to measure the scale and frequency of debris flow. Currently,conventional techniques are still unable to achieve quantitative research on the change in source erosion accumulation. To solve this problem,this paper takes the gully debris flow at the back of the Qionghai water plant in Xichang City as an example,based on two periods of optical images and high-precision DEM (Digital Elevation Model) by LiDAR before and after the rainy season,carries out quantitative evaluation of debris flow provenance erosion. The results show that: the fire area of the basin is 65%,and there are slope erosion provenance,landslide provenance and gully accumulation sources in the basin. According to the superposition analysis of two high-precision DEM datasets,the source erosion amount of debris flow before and after the rainy season is 12209 cubic metres. The source erosion area is characterized by wide distribution,large number and scattered development. The debris flow is mainly caused by slope material source erosion,and the majority of the erosion thickness is within 0.5 m. Therefore,there will be high frequency debris flow in the future.