A new method to prevent seepage erosion of loess slope toe using the combination of filter pipe and siphon drainage

Long-term agricultural irrigation on the top of the loess tableland will cause the toe of the slope to be eroded by seepage, which will induce repeated landslides. The coupled filter pipe and siphon drainage method (F&S method) is a new drainage method that combines existing methods and materials to focus on the mechanism by which seepage erosion occurs at the toe of the loess slope. The method was tested in the laboratory and the Heifangtai landslide group in Gansu Province, China. By testing the filtered water that was siphoned out during the tests and assessing the geomorphological changes after the field test, it was apparent that the F&S method effectively prevented the loess slope toe from being eroded and transported by the seeping groundwater. The drainage data and monitoring the groundwater level showed that the F&S method has a sensitive response capability and can automatically control the level of the groundwater. The results of the experiment with the physical model indicated the range of the influence of the F&S method on the loess, and this information, combined with the results of the field test, can be used to optimize the layout of F&S devices. The research showed that, compared with the methods that commonly are used to treat loess landslides, the F&S method has the advantages of strong pertinence, quick effect, simplicity, and low cost. This method is suitable for additional applications in loess areas.