| 西藏聂拉木县嘉龙湖冰湖溃决型泥石流危险性评价 |
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| 引用本文： | 柴波,陶阳阳,杜娟,黄平,王伟.西藏聂拉木县嘉龙湖冰湖溃决型泥石流危险性评价[J].地球科学,2020,45(12):4630-4639. |
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| 作者姓名： | 柴波 陶阳阳 杜娟 黄平 王伟 |
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| 作者单位： | 1.中国地质大学环境学院, 湖北武汉 430078 |
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| 基金项目： | 自然科学基金项目41702304自然科学基金项目41877253 |
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| 摘 要： | 冰湖溃决型泥石流是高原山区特殊的地质灾害，以西藏聂拉木县嘉龙湖为例，建立了一套冰湖溃决型泥石流危险性评价方法.以喜马拉雅山区1970—2015年气温波动频次和聂拉木冰湖溃决历史事件预测了未来10年嘉龙湖溃决的时间概率.利用遥感影像识别嘉龙湖上方不稳定冰体的范围和规模，采用美国土木工程师协会推荐公式和修正的三峡库区涌浪计算方法分析了冰川滑坡产生的涌浪规模，从涌浪波压力和越顶水流推力两方面预测了冰碛坝发生失稳的可能性.采用FLO-2D模拟冰湖溃决泥石流的运动过程，以最大流速和泥深表达了嘉龙湖溃决泥石流的危险程度.评价结果表明:2002年嘉龙湖溃决事件与当年气温偏高有关，未来嘉龙湖发生溃决概率高；冰川滑坡激起涌浪能够翻越坝顶，并引起坝体快速侵蚀而溃决；冰湖溃决泥石流对聂拉木县城河道两侧54栋建筑造成威胁.评价方法实现了冰湖溃决型泥石流危险性的定量分析，评价结果对聂拉木县城泥石流防灾具有现实意义.
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| 关 键 词： | 冰湖 泥石流 危险性评价 冰川滑坡 环境地质 |
| 收稿时间： | 2020-09-16 |
Hazard Assessment of Debris Flow Triggered by Outburst of Jialong Glacial Lake in Nyalam County,Tibet |
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| Abstract: | The debris flow caused by the outburst of glacial lake is a specific geohazard in the plateau mountainous area. With the study case of Jialong Lake, Nyalam County, Tibet, the hazard assessment model of the debris flow triggered by the outburst of glacial lake was established. Based on the analysis of temperature fluctuation from 1970 to 2015 in the Himalayas area and the historical events of glacial lake outburst in Nyalam County, the temporal probability of the outburst of Jialong Lake in the future 10 years is predicted. The range and magnitude of the unstable ice bodies above Jialong Lake are recognized relying on remote sensing images. The impulse waves generated by glacier landslide are determined with the formula recommended by American Society of Civil Engineers and the modified model of impulse waves in the Three Gorges Reservoir. The pressure of impulse waves and the thrust force of water current acting on the morainal dam are analyzed to assess the failure probability of morainal dam. FlO-2D was used to simulate the movement process of debris flow. The intensity of debris flow triggered by outburst of Jialong Lake were indicated with the maximum velocity and maximum depth of debris flow. The assessment results show that the outburst of Jialong Lake in 2002 was related to the high temperature in that year, and Jialong Lake still has a high probability of outburst in the future; the impulse waves caused by glacial landslide could climb over the top of the morainal dam, which cause rapid erosion and failure of the dam. The debris flow caused by the outburst of Jialong Lake would impact 54 buildings located along the river in Nyalam County. The model proposed in the paper realizes the quantitative hazard assessment of the debris flow caused by glacial lake outburst. The assessment results are of great significance for the risk management of debris flow in Nyalam County. |
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