近年來由於全球氣候異常的因素，導致降雨量的暴增，使得土石流、山崩
等自然災害發生的頻率越來越高，直接的影響到人民的生命財產安全，為了有效的去預測這些自然災害的影響範圍以及危害程度，我們可以藉由研究顆粒體的運動行為，來推估其流動特性。傳統的做法是透過實驗方法來進行探討，不過近年來透過應用數值模擬的方法，來進行顆粒流之研究也漸日益蓬勃發展。
本文的研究重點是著重在控制方程式中的摩擦項，以往在模擬顆粒的崩塌行為時，通常是採用庫倫摩擦力，本研究則是將Pouliquen & Forterre (2002)所提出的μ(I)-rheology 應用在摩擦項及對流項中，去探μ(I)-rheology 在變動地形上對流體行為的影響，包括土體厚度、土體滑移的距離等，且將控制方程式拓展至三維現地地形，並使用地形座標系(Tai and Kuo, 2008、Tai et al., 2012)將控制方程式建立在隨底床變動的座標軸上，以此來描述顆粒流的動態行為。

In recent years, due to abnormal climate factors, result in a surge of rainfall, it may increase the frequency of debris flow or landslides occusrs. It also affect people's lives and properties. In order to effectively predict the range of these natural disasters, we can study particle behavior of movement to estimates its flow characteristics. The traditional approach is through experimental methods, but for the past few years, the application of numerical simulation methods to study the granular flows has developed gradually.
In this paper, we focus on the friction term in the momentum equation.In the past, simulating the collapse behavior of particle usually used Coulomb friction, but we apply μ(I)-rheology to friction term and convection term to explore fluid behavior of the change in terrain, including thickness, run-out distance of granular flows. In addition, governing equation was extended to two-dimensional terrain, by using the terrain-fitted coordinate system to governing equation base on changes in the bed with the coordinate axes. To describe the dynamic behavior of granular flow.

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