Abstract The mechanical behaviour of debris flow agrees with Bingham pattern in general. The movement of debris flow requires overcoming the ultimate shearing force. Thus the debris may be accumulated in the valley and form a fan at the mouth. It used to be believed that the accumulation is the same in thickness and non-silting slope bases exist. But according to observation，survey and model experiment，in fact，the thickness along the accumulation is different. An accumulation equation of debris flow is established according to the assumption of different thickness. The computation is made of accumulation state approximate to the fact，and new viewpoints on debris flow is formed，that is，debris flow may move and be accumulated on any slopes，with different state and quantity.
2003, Vol. 22 
