Abstract:

Rising slope underground water level is an important factor inducing landslide, real-time discharge groundwater is an effective means to prevent the slope geological disaster. The siphon drainage with no power and flowing process by the change of the liquid level automatic control of the physical properties, which can meet the real time need of slope groundwater discharge. But the straw air accumulation leads to siphon destruction, and restricts slope of siphon drainage technology popularization and application. The air dissolved in the water due to the reduced pressure within the siphon overflow is the physical basis of the bubble forming. The experimental results show that, the siphon water inlet above the water surface of the vertical height of 3.5 m above will appear a large number of bubbles, through siphon vertex, bubble generation strongly merger into large bubbles. When the rainbow straw inlet head difference is bigger, bubble water bomb easily push the air bubbles are discharged from the water outlet. When the rainbow straw diameter is greater than 5 mm, slow siphon flow, occurs within the tube bubble accumulation, eventually destroying the siphon process, rainbow straw with diameter less than 4 mm, can form stable slug flow. Therefore, in order to keep the slope siphon process effective long-term, the rainbow straw can be chosen 5 mm in diameter in regular rainfall and slope ungroundwater rich area and less than or equal to 4 mm in diameter in non recurring rainfall area.

Key words: slope, siphon drainage, siphon pipe diameter, accumulation of air, slug flow