Experimental study on drainage mechanism of the self-starting drainage method for a slope

Conventional landslide drainage methods always seem to lack a long-term and efficient drainage capacity. Thus, it is necessary to develop a new drainage method that does not have these disadvantages. In this study, a new, self-starting drainage method is proposed based on the results of tests that were conducted with a physical model. The principle involved is that the drainage starts automatically when the level of the groundwater above the front end of the permeable pipes is higher than the orifice. A vacuum is generated in the permeable pipe after the flow begins in the pipe, and it is transmitted forward in the surrounding soil. Then, an unsaturated zone can be created in the soil during the transmission process, so the stability of the slope is expected to be improved. The results of the model test indicated that the diameter of the hose is an important factor that affects the drainage. Compared with siphon drainage, this method solves two problems simultaneously, i.e. it avoids the accumulation of air that could interfere with the siphon effect and it avoids the manual start-up.