基于LAHARZ的泥石流堆积范围预测模型的建立及应用

为了探究泥石流的堆积范围，利用LAHARZ软件，对北京市密云县泥石流沟喇嘛栅子南沟进行了数值模拟。结合泥石流沟小流域1：10 000数字高程模型图，模拟了泥石流的堆积范围。首先利用中国部分地区泥石流体积和堆积范围的数据资料，获得了泥石流体体积与其堆积范围的新的统计模型B=11.42V^0.7156；然后通过模拟沟道与实际沟道的对比，确定了最佳沟道阈值为15 000；再结合现场调查统计和降雨历史资料，确定了10年、20年、50年和100年一遇暴雨条件的泥石流体积值，分别为56 500、72 900、94 200和113 100 m³；最后在此基础上对该条泥石流沟的堆积范围进行了预测。结果表明，100年一遇的暴雨条件下泥石流堆积面积为48 729 m²，到达最远距离约为490 m，已影响下游村庄。

Establishment and Application of Prediction Model for Debris Flow Accumulation Area Based on LAHARZ

In order to explore the accumulation range of debris flow, a numerical simulation of the Lamazhazi debris flow in Miyun County, Beijing was carried out by using the LAHARZ software combined with the 1:10 000 DEM map of the small drainage basin. The authors utilized the data of volume and accumulation area of debris flow in some areas of China, and obtained a new statistical model for debris flow volume and its accumulation area. The optimal river threshold was determined to be 15 000 through comparing the simulated river channel with the actual river channel; combined with the on-site survey statistical and rainfall historical data, the debris flow volume thresholds for 10, 20, 50, and 100 years under heavy rain were determined to be 56 500, 72 900, 94 200, and 113 100 m³, respectively. The corresponding accumulation area of the debris flow trench is predicted as follows:the area of the debris flow under the condition of once-in-a-century rainstorm is 48 729 m², and the longest distance is about 490 m, which has an impact on the downstream villages.