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| DOI：10.13522/j.cnki.ggps.2021414 |
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| An Experimental Study on Wrapping Materials of Subsurface Drain for Farmland in the Downstream Hetao Irrigation District |
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HU Lingling, YANG Shuqing, LIANG Zhihang, et al
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1. Inner Mongolia Agricultural University, Hohhot 010018, China；
2. Inner Mongolia Teaching University, Hohhot 010022, China
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| Abstract: |
| 【Objective】 The efficacy and function of subsurface drain is controlled by materials used to warp it which in turn depends on soil texture in the region where they are installed. The purpose of this paper is to study these for drainage of croplands in the downstream Hetao Irrigation district. 【Method】The materials we used were 68 g/m2 and 90 g/m2 geotextile combined with sand particles with size in ranging from 0.3 to 3.0 mm used in the filtering layer. The experiment was conducted in lab, and the ability of the wrapped drain to drain water was measured using an in-house permeameter, from which we analyzed the effects of combination of different wrapping materials and sand size on permeability, soil retention and anti-clogging. 【Result】The system permeability coefficient of the 68 g/m2 geotextile is higher than that of the 90 g/m2 geotextile; the average permeability coefficient after the system stabilized is 4.5 times that of the stable value of the permeability coefficient of the system. Adjusting the hydraulic gradient can improve the permeability coefficient of the system. The variation of the stability value is small, and each treatment has a good water permeability and stability. Wrapping the drain with 68 g/m2 geotextile combined with 0.8 and 1.0 mm sand particles as the filtering layer improved the permeability coefficient significantly. The average soil loss of wrapping with 90 g/m2 geotextile was 0.5 g, meeting the soil conservation requirements and effectively preventing clogging. The clogging rate showed a high-low-high variation with the increase in sand size, and it was the lowest (26%) for wrapping with 68 g/m2 geotextile combined with 1.0 mm sand particles as the filtering layer.【Conclusion】Combining 68 g/m2 geotextile with sand particles sized 1 mm as the filtering layer was optimal for subsurface drains in the downstream farmlands of the Hetao Irrigation District. |
| Key words: subsurface drainage; geotextile; sand filter; screening; Hetao Irrigation District |
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