| 西藏洛隆县巴曲冰湖溃决型泥石流演进过程模拟研究 |
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| 引用本文： | 刘波,胡卸文,何坤,黄涛,韩玫,席传杰,文强,张晓宇. 西藏洛隆县巴曲冰湖溃决型泥石流演进过程模拟研究[J]. 水文地质工程地质, 2021, 48(5): 150-160. DOI: 10.16030/j.cnki.issn.1000-3665.202103104 |
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| 作者姓名： | 刘波 胡卸文 何坤 黄涛 韩玫 席传杰 文强 张晓宇 |
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| 作者单位： | 1.西南交通大学地球科学与环境工程学院，四川 成都 611756 |
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| 基金项目： | 国家重点研发计划（2018YCF1505401）；国家自然科学基金项目（41731285）；地质灾害防治与地质环境保护国家重点实验室开放式基金（SKLGP2018K011） |
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| 摘 要： | 巴曲冰湖溃决型泥石流紧邻川藏铁路某车站，可能对其建设及运营产生威胁。首先基于现场调查和遥感解译查明了巴曲泥石流的基本特征，采用规范公式计算了巴曲暴雨泥石流的动力学参数。然后采用无量纲堵塞指数（DBI）评价了巴曲沟内7个主要冰湖堰塞坝的稳定性。评价结果表明:巴曲1#冰湖堰塞坝的DBI值处于非稳定区，3#、4#和6#堰塞坝的DBI值处于非稳定区与稳定区之间，存在发生冰湖溃决的风险。最后，采用快速物质运动模拟软件（RAMMS）单相流数值方法，模拟分析了巴曲沟在4个极端场景下的冰湖溃决演进过程。模拟结果显示:巴曲冰湖溃决后的演进过程分为开始-汇流-冲出-停积四个阶段，共历时约4.5 h。在1#—4#及6#冰湖堰塞体全部溃决工况下，冰湖溃决泥石流在沟口的最大流速为5.92 m/s，最大深度为4.35 m，最大流量为1 954.42 m3/s，为暴雨型泥石流的5.1倍。除此之外，4个场景下冰湖溃决洪水的影响范围都经过拟建车站，泥石流最大深度分别为1.91，3.36，1.53，4.35 m。因此在车站设计时需采取排导槽或导流堤等工程措施进行防护治理。上述研究结果可为川藏铁路选线及青藏高原东部地区的冰湖溃决型泥石流防治提供参考。
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| 关 键 词： | 川藏铁路 冰湖泥石流 无量纲堵塞指数 快速物质运动模拟 溃决演进 |
| 收稿时间： | 2021-03-30 |
Characteristics and evolution process simulation of the Baqu gully debris flow triggered by ice-lake outburst in Luolong County of Tibet,China |
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| Affiliation: | 1.Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, Sichuan 611756, China2.Engineering Laboratory combined with National and Local of Spatial Information Technology of High-Speed Railway Operation Safety, Southwest Jiaotong University, Chengdu, Sichuan 611756, China3.School of Mathematics, Southwest Jiaotong University, Chengdu, Sichuan 611756, China4.China Railway First Survey & Design Institute Group Co. Ltd., Xi’an, Shaanxi 710043, China |
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| Abstract: | The Baqu glacial lakes outburst debris flow is close to a station of the Sichuan-Tibet Railway, which may threaten the construction and running of the railway. In this paper, the methods of in-site investigation and remote sensing were used to identify the basic geological characteristics of the Baqu gully. The kinetics parameters of debris flow were calculated by using the code-design-formulae method. Meanwhile, the stability of barrier dams of 7 glacial lakes in Baqu was evaluated based on the dimensionless blockage index (DBI). The results show that the DBI value of the 1# barrier dam was in the unstable region, and the DBI value of the 3#, 4# and 6# barrier dams were between the unstable region and the stable region, and there was a possibility of outburst. In this paper, we used RAMMS, a single-phase flow numerical method, to simulate and analyse the evolution process of glacial lakes outburst in the Baqu gully under 4 scenarios. The simulation results show that the evolution process is divided into 4 stages: initiation, confluence, runout and deposition, which lasted for 4.5 hours. The results also show that the maximum velocity, depth and discharge of the debris flow at the mouth of the channel were 5.92 m/s, 4.35 m and 1 954.42 m3/s (5.1 times of that of the rainstorm debris flow), respectively, under the condition of glacial lake 1#—4# and 6# outburst. In addition, the influence area of outburst flood in 4 scenarios affected the proposed station, and the maximum depth was 1.91 m, 3.36 m, 1.53 m and 4.35 m, respectively. Therefore, in the design of the station, it is necessary to take engineering measures such as drainage canal or diversion dike for protection and treatment, so as to ensure the safe running of the station. The above results can provide reference for the line selection of the Sichuan-Tibet Railway and the prevention and control of glacial lakes outburst debris flow in the Eastern part of the Qinghai-Tibet Plateau. |
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