強降雨現象所造成坡地的破壞為台灣常見的災害之一。本研究透過顆粒流實驗，簡化邊坡崩塌問題，以瞭解堆積土體破壞過程之流動特性及堆積型態。本研究使用均勻粒徑的細磨石，堆積成不同高寬比(a = Hi / Li)的塊體，在窄渠道中進行二維崩塌實驗。實驗分為定床和動床兩種底床條件，及顆粒間孔隙含水分別為飽和、未飽和與表面薄層水等三種含水情況，比較底床糙度和孔隙水壓對顆粒流動行為的影響。 堆積幾何型態以堆積長度、堆積高度及堆積角進行量化分析，結果顯示底床條件和含水量對堆積型態有明顯影響。本研究採用Voronoï cell概念的粒子影像測速法，分析流場速度分佈的情形。速度剖面在靠近自由表面處呈線性分佈，內部至擬靜態顆粒堆積層則為指數分佈，和邊壁穩定堆積流變學(SSH)的形式相符合，和Bagnold型態之速度剖面較不符合。 Slope failures triggered by heavy rainfall occur frequently in Taiwan. This study uses ballistic mill stone to perform two-dimensional granular collapse experiment. Besides changing the aspect ratio, a = Hi / Li, of granular column, we adopt three case of different void water saturations including saturated, unsaturated and pendular. The random column can either collapse on rigid bed or erodible bed. This study measure deposit distance, deposit height and deposit angle to evaluate the geometric morphology caused by bed friction and pore water pressure. Velocity profile can be recognized into two parts. Approaching free surface would be the linear profile and then the static region could find an exponential tail. The profile could be well describe by super stable heap(SSH) rheology and Bagnold rheology.
