Effect Of Hydraulic Gradient On Clogging Of Filter Layer Of Landslide Drilling Drainage System

Slope stability is often affected by rainfall infiltration,so it is important to remove groundwater in time to ensure slope stability.Currently,the commonly used groundwater removal technology in landslide prevention is drilling drainage system.To prevent soil particles from clogging of drainage pipe,the pervious pipe will be covered with geotextile.However,with the influence of the hydraulic gradient inside the slope,the seepage carries soil particles which stays in the filter layer when passing through the geotextile filter layer.In addition,seasonal closure caused by the dry season will also affect filter clogging.This study designs indoor physical model tests.The effect of hydraulic gradient on the clogging of drainage filter layers of slope under different soil conditions was studied.The main research results obtained are as follows:(1)The hydraulic gradient has a certain effect on the drainage filter clogging.The larger the hydraulic gradient is,the more soil particles are carried by the seepage with the influence of seepage pressure.Large amount of soil particles are deposited inside and on the surface of the geotextile filter layer,causing the filter layer clogging.Therefore,the larger the hydraulic gradient is,the more easily the drainage filter layer is blocked.(2)Closure intermittent has an impact on the drainage filter clogging.The study see that the longer the water stop,the more clay particles accumulate inside and outside the geotextile filter layer.And it is easier to form mud crust and permanent barrier clots,resulting in clogging of drainage filter.(3)According to the research,we propose engineering suggestions to solve the drainage filter clogging:The drainage hole should be made deep enough into the groundwater level,to keep a large part of the permeable pipes below the groundwater level and reduce the hydraulic gradient of the geotextile filter layer,and prevent the drainage filter layer from being blocked due to intermittent drainage.At the same time,that can avoid the slight clogging to affect the use of the project.