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| DOI：10.13522/j.cnki.ggps.2025304 |
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| Design and application of a practical and economical cross-section for parabolic trapezoidal channels |
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HE Zhengyu, HE Wuquan, LI Bo, ZHAO Keyi
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1. Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education,
Northwest A&F University, Yangling 712100, China; 2. Power China Northwest Engineering Corporation Limited, Xi’an 710065, China
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| Abstract: |
| 【Objective】Parabolic-bottom trapezoidal channels with hydraulically optimal cross-sections are efficient for water conveyance, but their narrow and deep geometry often causes construction difficulties and increases project costs in practical engineering applications. To address this limitation, this study proposes a practical and economical cross-sectional design method for the parabolic-bottom trapezoidal channel.【Method】Based on computational results of hydraulically optimal cross-sections, the relationship between the hydraulic parameters of practical economic sections and those of hydraulically optimal sections under different side slope coefficients was established through data fitting and numerical calculations. On this basis, we derived the formulas for determining the practical economic cross-section and developed the corresponding design procedure. The proposed method was verified against a numerical example.【Result】The results for the numerical example show that when the channel bottom slope was 1/6 000, the roughness coefficient was 0.015, the discharge was 12 m3/s, and the side slope coefficient of the trapezoidal section was 1.75. The calculated practical economic section of the parabolic-bottom trapezoidal channel (α=1.03) had a water depth of 1.838 m, a water surface width of 10.701 m, a flow area of 12.900 m2, and a wetted perimeter of 11.480 m. Comparative analysis with conventional trapezoidal and parabolic channels showed that under the same hydraulic conditions, the flow area of the section calculated by the proposed method was 1.08% smaller than that of the trapezoidal channel, and the wetted perimeter was reduced by 3.13%. In addition, the width-to-depth ratio of the section calculated by the proposed method was 2.61 times that of the parabolic channel.【Conclusion】Our results indicate that the practical economic cross-section of a parabolic-bottom trapezoidal channel improves hydraulic efficiency, while maintaining better constructability and economic performance. This makes the proposed method a suitable alternative for open-channel design. |
| Key words: parabolic-bottom trapezoidal channel; practical and economical section; hydraulic calculation; section design; engineering application |
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