| Cite this article: | 韩寒,李明思,张锦华,等.暗管断面结构对非饱和土壤中暗管排水排盐效果的影响[J].灌溉排水学报,0,():-. |
| Han Han,Li Mingsi,Zhang Jinhua,et al.暗管断面结构对非饱和土壤中暗管排水排盐效果的影响[J].灌溉排水学报,0,():-. |
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| Effect of Cross Section Structure of Subsurface Drainpipe on the Draining Water and Salt in Unsaturated Soil |
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Han Han1, Li Mingsi1, Zhang Jinhua1, Liu Xingshuang1, Xu Qiang1, Chen Wenjuan2
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1.College of Water and Architectural Engineering,ShiheziUniversity;2.Faculty of science ShiheziUniversity
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| Abstract: |
| 【Objective】The purpose of this paper is to study the efficacy of draining water and salt of subsurface drainpipe with different cross section structure in unsaturated soil, and to explore the effective drainage way for drip irrigated saline-alkali land.【Method】In this study, four kinds of subsurface drainpipe with treated cross section structure were selected to carry out drip irrigation and drainage tests by soil columns in laboratory.ST1 was the subsurface drainpipe with circular cross section and an impermeable bottom; T2, with equilateral triangular cross section and an impermeable bottom, T3, with circular cross section and an impermeable wing at the bottom, and T4, with equilateral triangular cross section and an impermeable wing at the bottom.SEach subsurface drainpipe was made of metal wire mesh, wrapped with non-polyester filament needled non-woven geotextile filter layer.SThe test soil was sandy soil, and each soil column was irrigated with 7 L water. Each test treatment had 5 replicates.SThe unsaturated soil water movement around the drainpipes with four kinds of cross section was simulated by MATLAB program.S【Result】Theoretical analysis showed that the cross surface width of T2 treatment was larger than that of T1 treatment for intercepting soil water, and its capacity adsorbing soil water was twice that of T1 treatment, as well as its inhibition effect on soil water flowing detour around the drainpipe cross section was slightly better than that of T1 treatment.SThe results of the experiments showed that the start time of soil water flowing from the outlet of T2 treatment was 7.45 h earlier than that of T1 treatment. When the cross section was added with impermeable wing at its bottom, the ability of inhibiting soil water flow detour around the cross section of subsurface drainpipe was enhanced, as well as the efficiency of discharge water and salt was improved.SIt was observed in experiments that the soil moisture content at 50 cm soil depth where the subsurface drainpipe bottom in T3 and T4 treatment was 17.02%±0.37 and 16.62%±0.77, respectively, which were lower than that at the same position in T1 and T2 treatments;Scompared with T1 and T2 treatments, the drain water of T3 and T4 treatments increased by 119.8 ml and 119.7 ml, and the salt discharge increased by 16.76 g and 18.83 g; the start time of soil water flowing from outlet of T3 treatment was 9.79 h earlier than that of T1 treatment, and the start time for T4 treatment was 3.47 h earlier than that of T2 treatment, respectively.SIt was further verified by numerical simulation that T2 treatment could suppress the soil water flow detour around the drainpipe cross section, and the ability of restraining the soil water flowing detour around the drainpipe cross section could be further improved by adding the impermeable wing at the bottom of the drainpipe.S【Conclusion】In unsaturated soil, the subsurface drainpipe with triangular cross section is better than that with circular cross section to inhibit the soil water flowing detour around the drainpipe cross section, and when the impermeable wing is added at the cross section bottom, its inhibition to the soil water flowing detour around the drainpipe cross section can be further improved, and its capacity of draining water and salt can be improved. |
| Key words: Subsurface drainpipe;SUnsaturated soil;Sdraining water and salt;SReclamation of saline-alkali land;SWater saving irrigation |
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