Clogging characteristics and salt blocking effect of geotextile envelope of subsurface drainage pipes in arid areas
Exploring the clogging characteristics of geotextile envelope of the subsurface drainage pipes and their impact on the drainage performance is of great significance for improving the efficiency of drainage and salt removal and ensuring the long-term operation of the project.This study took the typical subsurface drainage pipes in Xinjiang saline-alkali land as the research object,with samples tested have been in operation for 1,5 and 6 years.The mineral types and contents of the soil around the subsurface pipes,the clogging materials in the geotextile envelope,and the sedimentary materials in the pipes,the morphological characteristics of the clogging materials,and the impact of clogging on the permeability of the geotextile envelope were analyzed.The results show that there are two forms of clogging:the pores inside the geotextile envelope are clogged and the filter cake is formed at the soil interface.The clogging materials are mainly quartz sand and calcite,and are silt and clay particles.The permeability coefficients of the four sampling points decreased by 41.74%、93.55%、91.45%、and 1.61%,respectively.The analysis found that the geotextile envelope had physical clogging with silica as the main substance and chemical clogging with calcium carbonate as the main component;after clogging,a filter layer was formed on the surface of the geotextile envelope,which was mainly composed of sand and silt,and the clay content was less than that in the soil.The clogging was sensitive to the coefficient of soil uniformity and drainage saturation index,and the clogging was more serious at the sampling points where the coefficient of soil uniformity was less than 15 and the saturation index was greater than 0.5.This study can provide a useful reference for the prevention and control of clogging of subsurface drainage pipes in arid areas.
万方数据
维普
