不同水位条件下滑坡堵江堆积特性试验研究

Experimental study on deposition characteristics of landslide-induced river blockages under different water levels

摘要

【目的】滑坡是一种常见的地质灾害，当滑坡物质堆积堵塞河道时，可能引发一系列严重的次生灾害。当前研究多关注干河道滑坡堆积特性，对水体影响下滑坡堆积行为的系统认识尚不充分。水深变化对滑坡物质堆积过程与几何形态的影响规律有待揭示。【方法】通过室内物理模型试验，系统研究粒径为2.5 mm均匀石英砂在35°和45°坡度下，滑入干河道(水深0 cm)和不同水深(3 cm、6 cm、9 cm、12 cm)河道时的堆积特性，滑坡体积设为500 cm³、1 000 cm³、1 500 cm³和2 000 cm³。采用高速摄影和三维点云扫描技术记录堆积过程与形态，定义河道堆积体积率λ表征堆积程度。【结果】水深显著影响滑坡堆积过程与形态。干河道条件下，堆积体呈现前缘厚、后缘薄的不均匀分布；水体存在时，堆积物厚度分布更均匀，出现“双滑坡头”现象。河道堆积体积率λ随水深增加而减小，θ=35°时λ从干河道的0.36降至H=12 cm时的0.19,降幅达47.2%;θ=45°时λ从0.72降至0.41,降幅约43.1%。多元回归分析建立了水深、坡度和体积对λ的预测模型，对λ的影响程度由大到小依次为：坡度、滑坡体积和水深。【结论】水体通过增加阻力和缓冲作用，显著降低了滑坡物质的河道堆积比例。λ随坡度增大而增大，随体积和水深增加而减小。建议后续研究进一步考虑滑坡物质级配、河床动态变化等因素，以探究更为复杂条件下的堆积特性。相关研究成果为滑坡堵江风险评估与防治提供了定量依据。

Abstract

[Objective] Landslides are a common type of geological hazard that may induce a series of severe secondary disasters when the sliding mass accumulates and blocks river channels. Previous studies have mainly focused on deposition characteristics of landslides in dry channels, while systematic understanding of deposition behavior under the influence of water remains inadequate. The influence of varying water depths on the deposition process and geometric characteristics of landslide materials still needs to be examined. [Methods] Through laboratory physical model experiments, the deposition characteristics of uniform quartz sand with a particle size of 2.5 mm under slope gradients of 35° and 45° were systematically investigated as it slid into dry river channels(water depth of 0 cm) and channels with different water depths(3 cm, 6 cm, 9 cm, and 12 cm). The landslide volumes were set at 500 cm³, 1 000 cm³, 1 500 cm³, and 2 000 cm³. High-speed photography and three-dimensional point cloud scanning techniques were employed to record the deposition process and morphology. The river channel deposition volume ratio λ was defined to characterize the degree of deposition. [Results] Water depth significantly affected the deposition process and morphology of the landslide materials. Under dry river channel conditions, the deposits exhibited an uneven thickness distribution, with a thicker front and thinner rear. In the presence of water, the deposit thickness became more uniform, and a “double landslide head” phenomenon was observed. The river channel deposition volume ratio λ decreased with increasing water depth. At θ = 35°, λ decreased from 0.36 under dry river channel conditions to 0.19 at H = 12 cm, representing a reduction of 47.2%. At θ = 45°, λ decreased from 0.72 to 0.41, representing a reduction of approximately 43.1%. A multiple regression analysis was conducted to establish a prediction model relating λ to water depth, slope gradient, and landslide volume, with their influence on λ ranked as: slope gradient > landslide volume > water depth. [Conclusion] The presence of water significantly reduces the proportion of landslide materials deposited in river channels by increasing resistance and providing a buffering effect. The value of λ increases with increasing slope gradient, and decreases with increasing landslide volume and water depth. It is recommended that further studies incorporate factors such as the gradation of landslide materials and dynamic changes in the riverbed to explore deposition characteristics under more complex conditions. These findings provide a quantitative basis for risk assessment and mitigation of landslide-induced river blockages.

关键词

滑坡灾害 / 堆积特性 / 河道堆积体积率 / 水深 / 物理模型试验 / 影响因素 / 地质灾害 / 风险评估

Key words

landslide hazard / deposition characteristics / river channel deposition volume ratio / water depth / physical model experiment / influencing factors / geological hazard / risk assessment

基金资助

中国长江电力股份有限公司项目(Z412302052)

国家自然科学基金项目(52479070)

国家自然科学基金项目(52309101)