“东川型”排导槽结构对泥石流流速影响的实验研究

Experimental Study on the Relationships between the Velocity of Debris Flow and Structure of the Dongchuan Debris Flow Channel

消能肋槛和排导槽纵比降是控制"东川型"泥石流排导槽内流体运动的两个关键因素。泥石流流速是反映排导槽工程输移力及对排导槽的冲刷淤积破坏的重要参数之一。通过实验,对固定配比的泥石流流体在不同的肋槛组合下的排导槽中的流速进行了研究,结果表明:(1)肋槛间距从40cm增加至60cm时,泥石流流速先增加后减少,在间距50cm时达到最大值;(2)肋槛高度对泥石流流速的影响非常复杂,在不同的肋槛间距和纵比降下表现不同的相关关系;(3)纵比降对排导槽内的泥石流流体基本呈正相关;(4)得到了肋槛间距与肋槛高度之比值N与泥石流流速V之间关系的数学表达式:V=0.0341N+C,其中C为常量。

The debris flow velocity is one of important parameters on describe the transport capacity, deposition and erosion damage of debris flow channel. The Dongchuan debris flow channel is the most wide used type of channel with the characteristic of soft foundation energy dissipation in China, which is created by pre-scholars in the long time practice of debris flow mitigation. For the Dongchuan Channel, the threshold and gradient are two key factors to control the movement of debris flow in channel. By using a dynamic experimental system of debris flow, a series of indoor model tests on debris flow passing through channel with diffident threshold parameters are carried out. The follow test results are drawn ： （1 ） When the spacing of threshold increase from 40 cm to 60 cm, the velocity is increased first and then reduced, it reaches maximum when the spacing of threshold is 50 cm; （2） The relationship between the height of threshold and velocity is very complex. When the threshold spacing and gradient change, the relationship would change too ; （ 3 ） The relationship between the gradient and the velocity of debris flow is in positive correlation; （4） One formula has derived to express the relationship between the ratio of the threshold spacing and height N and the velocity of debris flow V from testing, which is V=0. 0341N ＋ C,where C is a constant number,which is varying in 1.01-1.41 and confined by gradient of the debris flow channel.