中文摘要：

崩岗侵蚀过程及其侵蚀量的精准量化分析,是研究崩岗发育机理及其发展演化的基础,也是测算崩岗流域产沙输沙的前提,对崩岗预防和治理以及水土保持和生态建设具有理论和现实意义。本研究应用三维激光扫描技术,大致以半年为周期,在6次定位监测基础上,以广东五华县莲塘岗崩岗为例,对崩岗侵蚀过程进行了定量分析。研究表明,莲塘岗崩岗年平均侵蚀量为833 m3,其中雨季平均侵蚀量为499 m3,干季平均侵蚀量为291 m3,侵蚀模数高达222 408 t/（km2·a）。24 h降雨量大于等于50 mm的暴雨、特别是大于等于100 mm的大暴雨对崩岗侵蚀影响很大,暴雨总量与崩岗侵蚀量具有正相关关系。崩壁之下的崩积锥部位侵蚀量最大,占总侵蚀量的55.6%。40°-60°坡面的侵蚀量最大,占总侵蚀量的49%。最大侵蚀强度（单位面积侵蚀量）位于50°-60°和70°-80°的两个坡度区间。最为剧烈的侵蚀区为主沟与支沟两侧及沟头部位,侵蚀深度均大于1 m,最大深度可达2.5 m。前3个监测周期,沟道以快速下切、侧蚀和溯源侵蚀为主,兼有小规模崩塌;后2个监测周期,以重力崩塌为主,沟道侵蚀减弱。崩岗地形变化导致其水力与重力作用交替进行,使崩岗侵蚀呈现出波动式变化。

英文摘要：

Three-dimensional laser scanner（Leica Scan Station 2） was used to measure Liantanggang collapsing hill and erosional gully in Wuhua County of Guangdong Province for 6 times during 2011-2013. About half a year as an interval, and through ArcG IS, high-solution analyses of measurements was conducted to study the spatial and temporal variations of the erosional processes and sediment yield in the watershed of Liantanggang. The average erosional volume was 499 m3 in rainy season, and was 291 m3 in dry season. During the 3 years measurement, the average annual erosional amount was 833 m3 and the erosional modulus was 222 408 t/（km2·a）. The heavy rainstorm more than 100 mm within 24 h greatly influenced the collapses. Rainfall of rainstorm during each measuring period was positively correlated with the erosional amount. The intense erosional zones located on the colluvial cones at the elevations between 111-131 m, accounting for 55.6% of the total erosional amount, which indicates that the erosional rate in the middle-lower parts of the watershed is the greatest. The slopes of 40°-50° was the largest erosional amount, then the slopes of 50°-60°, and both them accounting for 49% of the total erosional amount of 1 019 m3. The sediment yield per square meter increased with the gradient, which means the erosional processes are more intense in steeper slopes. The average maximum erosional amount per square meter was located on the slopes of 70°-80°. The average erosional depth for each measuring period was 0.105 m. During the period of all the measurements, the severe erosion was found in the main and branch channels including their sides, and at the gully heads. The accumulative erosional depth was greater than 1 m, and the maximum depth was more than 2.5 m. Within the period of five measurements, the erosional modes showed as in the first 3 measuring periods, rapid down-cutting, lateral and retreated erosions were the main modes. In the last 2 measuring periods, there were dominantly gravitational erosions