考虑堆积区宽度影响的滑坡碎屑流运动与堆积过程物理模型试验研究

    MODEL TESTS OF RUN-OUT AND DEPOSITION PROCESS OF LANDSLIDE DEBRIS CONSIDERING INFLUENCE OF DEPOSITING ZONE WIDTH

    • 摘要: 堆积区宽度会显著影响滑坡碎屑流运动与堆积过程,而目前该方面研究却相对较少。本文设计了一种水平滑段宽度可变的物理模型试验装置,在此基础上开展了一系列物理模型试验。试验获取了不同宽度水平滑段条件下颗粒流运动与堆积过程的图像和数据,分析了颗粒流速度分布和堆积特征,进一步结合数值模拟探讨了颗粒流运动机制与堆积特征成因。结果表明:颗粒流在倾斜滑段随运动距离增加逐渐离散且离散范围也逐渐增大;颗粒流在水平滑段的运动速度随水平滑段宽度增加逐渐减小,运动速度方向发生偏移且随水平滑段宽度增加更加显著;颗粒流在水平滑段的堆积长度随水平滑段宽度增加逐渐减小,堆积宽度逐渐增加,堆积面积先减小后增加;数值模拟结果表明:碰撞是颗粒间主要能量传递形式,摩擦是主要耗能形式,随着水平滑段宽度增加,颗粒流在水平滑段颗粒间的碰撞次数逐渐减少,颗粒向两侧滑动展布,摩擦耗能使得颗粒流堆积宽度增加而堆积长度减小。

       

      Abstract: It is noted that the run-out and deposition processes of rockslide-avalanche can be greatly affected by the width of the depositing zone. However, there are limited studies regarding the influence of the width of the depositing zone on the run-out and deposition processes of rockslide-avalanche in literature. In this study, a model test system with an easily adjustable width of the depositing zone is designed and used for a series of model tests. During the tests, the images and data of the run-out process and deposition behaviors, with different widths of depositing zone, are collected and used for deriving the velocity and deposition behaviors of the granular flow. Further, numerical simulations are undertaken to reveal the underlying mechanisms of the run-out and deposition behaviors. On the basis of the obtained results, the following conclusions are drawn. The divergence of the sliding materials on its inclined sliding path tends to increase with the sliding distance. The sliding velocity of the materials in the depositing zone decreases with the width of the depositing zone, the sliding direction of the materials changes in the depositing zone and this change becomes more distinct with the increase of the width of the depositing zone. The increase of the width of the depositing zone tends to lead to the decrease of the length of the granular flow deposition in the depositing zone while the increase of the width of the granular flow deposition. The area of the granular flow deposition decreases first and then increases with the width of the depositing zone. Numerical simulations indicate that collision is the main type of energy transfers among the sliding martials while friction is the main type of energy consumption. With the increase of the width of the depositing zone, the frequency of collisions decreases and the sliding materials tends to move towards two sides. The energy consumption induced by friction could lead to the increase of the width of the granular flow deposition while the decrease of the deposition length.

       

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