| 引用本文: | 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,2022,41(6):131-139. |
| 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,2022,41(6):131-139. |
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| 摘要: |
| 【目的】研究不同断面结构的暗管在非饱和土壤中的排水排盐效果。【方法】选用了4种断面结构的暗管在室内进行土柱滴灌排水试验；其中，T1为底部不透水的圆形暗管，T2为底部不透水的等边三角形暗管，T3为底部带不透水翼的圆形暗管，T4为底部带不透水翼的等边三角形暗管；各暗管均由金属丝网构成，外裹无聚酯长丝针刺无纺土工布作滤层。供试土壤为砂土，每个土柱灌水7 L，每个处理设置5个重复。利用MATLAB平台对4种暗管周围的非饱和土壤水分运动进行了模拟。【结果】T2处理的拦截面宽度大于T1处理，其对水分的吸持能力是T1处理的2倍；且对土壤水分绕流现象的抑制作用比T1处理的性能略好。T2处理的暗管出水时间比T1处理的提早7.45 h；对暗管增加底翼后，可增强其抑制土壤水绕流的能力，提高其排水排盐效果；其中，T3、T4处理的暗管底部50 cm处的土壤含水率分别为17.02%±0.37%和16.62%±0.77%，均小于T1、T2处理同位置处的土壤含水率；T3、T4处理的排水量分别比T1、T2处理的值增加119.8 mL和119.7 mL，排盐量增加16.76 g和18.83 g；T3、T4处理的暗管出水时间分别比T1、T2处理的出水时间提前9.79 h和3.47 h。通过数值模拟进一步验证了T2处理可以抑制绕流；暗管增加底翼后，可进一步提高其抑制绕流的能力。【结论】在非饱和土壤中，三角形断面暗管抑制土壤含水率绕流的作用好于圆形断面暗管的同类能力；暗管增加底翼后，可以进一步提高其对绕流现象的抑制作用，提高其排水排盐能力。 |
| 关键词: 排水暗管；非饱和土壤；排水排盐；盐碱地治理 |
| DOI：10.13522/j.cnki.ggps.2022009 |
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| Effect of Cross Section of Subsurface Drain on Its Performance |
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HAN Han, LI Mingsi, ZHANG Jinhua, LIU Xingshuang, XU Qiang, CHEN Wenjuan
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1. College of Water and Architectural Engineering, Shihezi University, Shihezi 832003, China;
2. Faculty of Science Shihezi University, Shihezi 832003, China
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| Abstract: |
| 【Objective】Subsurface drain is an engineering technology to control groundwater table not exceeding a critical depth. Its performance depends not only on soil properties but also on design parameters. The purpose of this paper is to investigate the impact of geometrical configuration of the drain on its performance in controlling water and salt movement in the soil. 【Method】We compared four cross sections: circular section with an impermeable drain bottom (T1); equilateral triangular section with an impermeable bottom; circular section with an impermeable wing at the drain bottom; equilateral triangular section with an impermeable wing at the drain bottom. All drains were made by metal wire meshes; they were wrapped by non-polyester filament and perforated non-woven geotextile filter layer. The drainage experiment was conducted in soil columns repacked with a sandy soil. Each column was irrigated by 7 L of water. During the experiment, we measured soil water movement around the drain; water flow in the soil was simulated using a MATLAB program. 【Result】The time that water started exiting the outlet of the drain in T2 was 7.45 h ahead of that in T1. Adding an impermeable wing at the bottom of the drain inhibited water exfiltration thereby improving drainage efficiency. It was found that soil moisture content at the bottom of the drain (50 cm deep) in T3 was 17.02%±0.37% lower than that in T1, while that in T4 was 16.62%±0.77% lower than that in T2. T3 drained 119.8 mL of water and 16.76 g of salt more than T1, while T4 increased 119.7 mL water drainage and 18.83 g salt removal than T2. The time that water started exiting the outlet of the drain in T3 was 9.79 h earlier than that in T1, while the starting time for water to exit the drain in T4 was 3.47 h ahead of that in T2. Numerical simulation confirmed that T2 reduced water exfiltration more, especially with an added impermeable wing at the bottom of the drain, and it is hence most effectively in draining water and removing salt. 【Conclusion】Subsurface drain with triangular cross section was more effective in inhibiting water exfiltration, especially after adding an impermeable wing to its bottom. |
| Key words: subsurface drain; unsaturated soil; draining water and salt; reclamation of saline-alkali land |
