Horizontal drainage hole is the most widely used drainage technology in landslide treatment.But the clogging problem seriously affects its service life and efficiency.Mechanical clogging is the main clogging form in horizontal drainage hole.The siltation is more serious when the drainage holes are located near the underground water table.A series of physical model experiments were carried out to analyze the influence of elevation

intermittent drainage and re-seepage problems on the clogging of horizontal drainage hole.Meanwhile

the clogging mechanism of horizontal drainage near the underground water table was analyzed according to the physical model test results.The results show that the location of the silt blockage in horizontal drain hole is related to the seepage path.A small elevation angle is the main reason for the clogging of horizontal drainage hole.Furthermore

intermittent drainage and re-seepage problems aggravate the clogging in horizontal drain hole.Sediment deposition in the water and fine sediment flocculation are the cause of mechanical clogging in horizontal drain hole.