| 泥石流容重的时空变化特征及影响因素研究 |
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| 引用本文： | 黄海,刘建康,,杨东旭.泥石流容重的时空变化特征及影响因素研究[J].水文地质工程地质,2020,47(2):161-168. |
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| 作者姓名： | 黄海 刘建康 杨东旭 |
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| 基金项目： | (四川省国土资源厅“8.8”九寨沟地震灾区生态化地质灾害防治重大科技支撑研究课题(KJ-2018-24)；中国地质调查局地质调查项目(DD20190644；DD20160251；12120113011000)；支撑服务川藏铁路规划建设地质调查（20190505）) |
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| 摘 要： | 为了探索泥石流容重在不同时空条件下的动态演化特征及其影响机制，基于蒋家沟1995年以来的泥石流观测数据和汶川震区2008年以来的调查资料，研究了典型泥石流灾害的水土耦合过程和容重动态变化的互馈作用，对比分析了常用的容重计算方法在汶川震区泥石流计算中的差异性，并从计算公式和灾害特征两方面探索误差产生的原因。结果表明:容重随泥石流孕灾条件的时空演化而动态变化；在时间尺度上，物源活动性与容重呈正相关，物源赋存状态从极度活跃演化至高度活跃时，容重将下降10.0%～27.8%；泥石流峰值流量与容重成幂函数关系，容重随着流量增大而增大，但具有明显的上限值；在空间尺度上，容重与沟床纵比降变化趋势一致，随着侵蚀作用而增大，淤积作用而减小；常用的6种泥石流容重计算方法在龙门山区的应用结果偏差幅度为10%～30%，仅使用某种计算方法确定容重参数将导致一定误差。文章最后利用物质组成计算容重的方法，基于冲淤总量和颗粒参数建立了不同沟道段泥石流容重经验计算公式，并在雍家沟泥石流进行应用，结果显示该方法针对具有完整序列观测资料的泥石流沟，具有较好的适用性。
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| 关 键 词： | 泥石流 容重 动态演化 孕灾条件 计算方法 |
| 收稿时间： | 2019-07-24 |
A study of the characteristics and influencing factors of spatial-temporal changes in the debris flow density |
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| Abstract: | Density is the most fundamental parameters in the calculation of debris flow movement characteristics. In order to explore the dynamic evolution of the debris flow density under different spatial-temporal conditions, based on the observation data of debris flow in the Jiangjia Gully since 1995 and the investigation data of debris flow hazards occurred in the Wenchuan earthquake area since 2008, the interaction of fluid-soil coupling process and density of typical debris flow disasters is studied, and several methods of density calculation are used in the Wenchuan earthquake area and the differences in the calculation formula establishment and the disaster characteristics are analyzed. The results show that the density changes dynamically with the evolution of formation conditions of debris flow. On the temporal scale, the activity of the solid materials in the gully is positively related to the density, and the density will decrease by 10.0%~27.8% when the solid materials evolve to highly active from extremely active. There is a power function relationship between the density and peak flow of debris flow, and it has an obvious limit when the density increases with the increasing flow. On the spatial scale, the change trend of density is consistent with the channel gradient, which increases with erosion and decreases with sedimentation. The deviation of these calculation results in the Longmen mountain area is in the range of 10~30%, suggesting that using only one method for density calculation is very much likely imprecise. Empirical formula are established based on the total amount of erosion and deposition, and particle parameters are practically applied to the debris flow at the Yongjia Gully. The research lays a foundation for calculation of the density based on the disaster history and evolution of geological conditions, and are of practical guidance significance in the evaluation and prevention of debris disaster and the calculation of dynamic parameters. |
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