基于FLO-2D的联合溪沟泥石流运动特征及防治对策

Debris Flow Motion Feature and Control Measures of Lianhexi Valley Based on FLO- 2D

湖南省岳阳县联合溪沟无泥石流灾害历史,但于2011年、2012年连续两年暴发特大型泥石流。在实地调查中取得了该泥石流沟的地形、物源、水源等基础资料,并重点分析沟内堆积物颗粒粒径分布规律,总结了该泥石流的发育特征:在地形因素的主导下,沟道水动力条件不断变化,泥石流呈现出冲刷—淤积—运动—堆积的特点。利用FLO-2D模拟泥石流的活动范围及掩埋深度,并进行灾情验证,结果表明FLO-2D模拟计算结果与实际灾情基本一致。针对该泥石流沟的复杂性、独特性,提出以拦挡坝、桩林式格栅坝、清淤护岸工程相结合的泥石流工程治理措施。

In 2011 and 2012,the hundred years of rainfall struck the Yueyang County,causing severe debris flow in Lianhexi Valley. Based on the survey data,the formation of debris flow after extreme heavy rainfall was analyzed,including terrain conditions,Provenance conditions,water conditions. Analysis suggested that Mumiaoxi Valley and Gaojiaxi Valley of the six ditches played an important role and saved a large number of stones in the channel,which originated from slope bedrock with cracks. With channel sediment particle size as the study object,the motion law of debris flow suggested that the effect of topog-raphy was the main controlling factor,which changed hydrodynamic conditions of debris flow gully and made the debris flow go and stop,repeating this pattern. Employing the FLO-2D software,the study ar-ea has been divided into 8 180 grids,50 × 50 meters,using ArcGIS software,the DTM data of the study area was obtained,various parameters were inputed into FLO-2D software. Finally,FLO-2D simula-tion results showed that the submerged depth of debris flow ranged from 0. 5-9. 4 meters,and the flow velocity ranged from 1. 1-4. 6 m/s. Compared with the the actual disaster situation,the simulation result based on the FLO-2D model was in conformity with that of field survey,showing that most houses would be submerged by about 0. 5 meters,the fastest velocity of debris flow was in the vicinity of the scarp. Fur-thermore,it is suggested that blocking dam,grille dam,desilting revetment Engineering should be com-bined to prevent the harmful debris flow.