以乾砂箱並利用電腦控制吸嘴移動系統進行河道逐步下切對邊坡反應之類比模擬

Abstract

坡度逐漸變陡會引發間歇性的乾砂崩塌，類似於自然環境中的山崩現象。同樣地，河道逐漸下切也會導致周期性的邊坡不穩定。為了探討此過程對集水區地形與坡面動態的影響，我們進行理想化的乾砂箱實驗，以深入了解山區滑坡模式和動力學。 實驗裝置是一個填滿乾砂的砂箱，並結合了受 3D 列印噴嘴啟發的抽吸機構組成，透過吸塵器產生負壓吸力移除砂粒。本研究透過吸嘴依循預設路徑移動的方式，模擬河道下切，並觸發鄰近坡面的崩塌。 為了驗證吸砂系統的可行性，我們首先讓吸嘴垂直下降以形成擴大的錐形凹坑，測試吸力機制的基本功能。接著，透過吸嘴沿著曲線以恆定速度移動模擬河道下切過程，並以電腦控制其路徑以確保精準度。實驗中使用電子磅秤量測質量流率，並配置兩台相機同步記錄砂箱內部變化。透過影像分析，追蹤每次崩塌發生時表面移動的區域，並將崩塌面積與質量流率的變化加以比對與同步分析。 實驗結果呈現了坡面在河道下切作用下的演化機制，並顯示了坡面所產生的山脊線、崩塌事件與坡度變化。

Progressive slope steepening can trigger episodic dry sand avalanches, resembling landslides in natural environments. Similarly, gradual river incision induces periodic slope instability. To investigate its impact on catchment topography and slope dynamics, we conduct idealized dry sandbox experiments, offering insights into landslide patterns and dynamics in mountainous regions. The setup consists of a box filled with dry sand and a suction mechanism inspired by 3D printing nozzles, using a vacuum cleaner to remove sand with negative suction pressure. The experiments simulate river incision and trigger avalanches on adjacent slopes by applying suction through a nozzle that follows prescribed paths. To validate the system, we first use a vertically descending suction nozzle to create an expanding conical pit, testing the suction mechanism. Next, we simulate river incision by moving the nozzle at constant speed along a curved path. The path is computer-controlled for precision. We monitor the evolution of the avalanches with an electronic scale for mass flux and two cameras to capture the sandbox. Image analysis tracks areas of surface motion during the sequence of landslides. Finally, we synchronize and compare the landslide area and mass flux measurements. The results, including the formation of ridges, avalanches, and slope adjustments, provide valuable insights into the behavior of slopes under conditions of gradual river incision.