本文目地在於探討土石流於堆積侵蝕時之孔隙水壓變化，並配合土石流理論找出影響孔隙水壓變化之關鍵機制及影響因子。本文研究方法為利用小尺度流槽實驗量測土石流底床之孔隙水壓並搭配高速攝影機拍攝即時流況變化，並藉由粒子影像測速法(Digital Particle Image Velocimetry，DPIV)獲取其速度場資料。
土石流可視為土砂顆粒與水的混合流體，受重力驅動在坡面由高處往低處流動。探討顆粒間孔隙流體所產生的壓力有助於瞭解土石流內部應力與土石流流動變化，而土石流內部應力除了土砂顆粒與水各自的應力與物體力外，還有土砂顆粒與水之間的交互作用力，包含浮力、黏滯阻力等。這些力作用的變化皆會造成土石流產生不同的流況變化，因此本文將以此為基礎分析實驗量測之土石流在堆積與侵蝕時底床孔隙水壓力變化。
在剛性底床條件下，實驗結果顯示除了水面高程提供的孔隙水壓外，流動顆粒會產生額外的孔隙水壓；在可侵蝕底床條件下，由於底床有一層可變動的堆積體，會受到上方流場流動而產生匍匐作用，造成底床表層緩慢移動的現象，因此除了水面高程以及流動顆粒外，因匍匐作用產生移動的底床顆粒也會提供孔隙水壓。本文提出其匍匐作用與流場的流動深度、速度，且與動床底床介質交換有關。經相關的實驗數據比較探討後可得知匍匐作用所產生之孔隙水壓與上方整體流動層的質量流率和動量傳輸成線性相關。
本研究之成果顯示了在對於土石流孔隙水壓探討時，相比於傳統的靜水壓假設，土砂與流體間的交互作用為不可忽略的因素。

The current study aims at investigating the basal pore-fluid pressure of debris flows, especially when deposition or erosion is taking place. A series of experiments was designed and performed in a narrow channel, where the basal pore water pressure of sand-water mixture was measured. Simultaneously, a non-intrusive velocity measuring technique, Digital Particle Image Velocimetry (DPIV), was applied in this study. According to the bed condition, two cases were taken into account: one is rigid bed and the other one is erodible bed. In the case of Rigid bed, extra basal pore-fluid pressure is measured which is generated by the suspending sediments. In the Erodible bed case, additional extra pore-fluid pressure is identified, which is suspected to be caused by the creeping motion at the bottom. This additional extra pore-fluid pressure is found also during the process of deposition and erosion. The additional extra pore-fluid pressure, caused by creeping motion, can be assessed by mass flow rate and bed-sediment entrainment above the bed. In addition to the assumption of hydrostatic pressure, the results of both cases reveal that the extra pore-fluid pressure of debris flows plays a non-negligible role.

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