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Study on estimation for the destruction of the moraine dam for the risk assessment on the disaster that causes glacier lake outburst flood

冰湖溃决洪水灾害风险评估中冰碛坝破坏估算研究

基本信息

批准号：
15360258
负责人：
UMEMURA Jun
金额：
$ 2.82万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360258/
关键词：
glacial lake outburst flood Moraine dam Field survey Ice body remaining moraine dam Seismic exploration Risk evaluation for the outburst 氷河湖決壊洪水(GLOF)現地計測室内実験斜面安定解析エンドモレーン斜面安定力学試験物理試験地形解析河岸浸食

项目摘要

About the realities of the glacial lake outburst flood (GLOF) damage, the following results were obtained ;1)Starting of GLOF is a debris flow, and a large amount of debris is sedimented a few km down the moraine dam.2)Afterwards, the flow erode the bed of valley and down a long distance over several tens km while inducing the collapse of both sides intermittently.3)At the collapse slopes caused by GLOF, its vegetation is not recovered in 20 years or more. Due to so, these slopes have been eroded intermittently for a long term. Therefore, it is necessary to consider not only the case of generation of large-scale GLOF, but also a long series of measures of the recovery of this vegetation after it is generated.About the stability of the moraine dam, the following results were obtained ;1)At the front of moraine dam, the thick moraine sediment, 60m more thick, was measured by the seismic explorations. The results clearly show that the moraine dam was been steady because its sediment acts … More as the counter weight for slide of the ice body remaining into the moraine dam.2)It was found from the result that the melting of the ice body remaining the moraine dam is important for the estimating of the stability of the moraine dam. In addition, it is necessary to observe the surroundings, slopes and hanging glacier of the glacial lake (not only dam site) by the aero photograph. These are important points for evaluating the collapse risk.And, the temperatures into the moraine dam had never be 0℃ or less through the year. On the lake water, these of every depth of the lake also be 0℃ more in winter season. Therefore, the authors pointed that the simulation of melting of the ice body is needed for the risk evaluation of GLOF, because the condition of ice body has been progressing the melt now.Finally, the authors indicate the countermeasures ;1)Somebody says that the blasting of the moraine dam is most effective for reduce the GLOF. However, the authors do not concur with such kind of opinion. At first, the blasting of the ice body is difficult due to its scale. The moraine dam is also due to its composed loose. In addition, if GLOF is generated, the erosion of the slopes is caused for a long term.2)The subsidence of ice body has been progress too slowly. So, if we can control it, it will become the effective countermeasure for GLOF. Less

针对冰湖溃决洪水灾害的实际情况，得出以下结论：1）GLOF的起始是泥石流，大量的泥石流沉积在冰碛坝下数km处; 2）随后，水流冲刷河床，向下长距离地沉降数十km，同时诱发两侧的崩塌; 3）在GLOF崩塌斜坡处，其植被在20年或更长时间内都无法恢复。因此，这些斜坡长期以来一直受到间歇性的侵蚀。因此，不仅要考虑大规模冰碛物形成的情况，而且要考虑冰碛物形成后植被恢复的一系列措施。关于冰碛坝的稳定性，主要研究结果如下：1）在冰碛坝坝前，通过地震勘探测得冰碛物较厚，厚度超过60 m。结果表明，冰碛坝是稳定的，是由于泥沙的作用 ...更多信息 2）研究结果表明，残留冰体的融化对冰坝的稳定性评价具有重要意义。此外，还需要通过航空摄影观察冰湖（不仅是坝址）的周围环境、斜坡和悬冰川。这些都是评价冰碛坝崩塌危险性的重要指标，而且冰碛坝的入坝温度多年来从未低于0℃。在湖水上，这些湖的各深度在冬季也多为0℃。因此，在冰碛物融化的危险性评价中，需要对冰碛物的融化过程进行模拟，因为目前冰碛物的状况正在促使冰碛物的融化，最后提出了相应的对策：1）有人认为冰碛物坝的爆破是减少冰碛物融化的最有效的方法。然而，作者不同意这种观点。首先，由于其规模，冰体的爆破是困难的。冰碛坝也是由于其组成松散。另外，一旦形成冰流失稳，对坡面的侵蚀作用将持续很长时间。因此，如果能够有效地控制它，它将成为应对GLOF的有效措施。少