基于Massflow模型的冷渍沟泥石流工程治理效果评价

Massflow model-based evaluation on effect of engineering treatment of debris flow in Lengzigou Gully

强震影响区、充沛的雨量、特殊的地质环境使得西昌市冕宁县区域地质灾害频发。现场调查冕宁县冷渍沟泥石流,获取了泥石流的降雨雨量及泥石流密度等模拟的相关数据,利用Massflow和ArcGis软件,再现了冷渍沟泥石流的运动特征,得到泥石流工程治理前、后的危险性评价图。对比工程治理前后模拟图得出:工程治理前,冷渍沟泥石流最大流速8.55 m/s,最大泥深7.5m,沟道高危险区占77%、中危险区占13%、低危险区占10%;工程治理后,拦挡坝位置泥深最大,沟道堆积物减少且沟道与安宁河交汇处的危险区范围变小,危险程度明显减弱。评价结果表明:冷渍沟泥石流拦挡坝能很好地对泥石流冲出物进行拦截,从而达到降低沟域危险程度的工程治理目标。

Strong earthquake impacted area,abundant rainfall and special geological environment make regional geological disasters frequently occur in Mianning County of Xichang City.Through the in situ investigation of the debris flow in Lengzigou Gully in Mianning County,the relevant data for simulating the rainfall amount and the density of debris flow during the debris flow are obtained,and then the movement characteristics of the debris flow in Lengzigou Gully is reproduced,while the hazard assessment maps before and after the engineering treatment of the debris are got as well.Through comparing the simulation maps before and after the engineering treatment,it is obtained that the maximum flow velocity of the debris flow is 8.55 m/s with the maximum mud depth of 7.5m,while the high hazard area accounts for 77%,mid-hazard area accounts for 13%and low hazard area accounts for 10%before the engineering treatment;after the engineering treatment,the mud depth at the location of the debris flow blocking dam is the largest with the decrease of the deposit in the gully and the reduction of the hazard area at the confluence of both the gully and Anninghe River,thus the degree of the hazard is obviously weakened.The evaluation result shows that the blocking dam for the debris flow in Lengziguo Gully can better intercept the debris washed out from the debris flow and then get the engineering treatment target of decreasing the hazard degree within the gully area.