The response of hydraulic conductivity to air-trapped saturation in a dissolution process of trapped-air in quasi-saturated fine sands media
The hydraulic conductivity of a quasi-saturated aquifer decreases with the increase of air-trapped saturation, but it is difficult to obtain a continuous data on air-trapped saturation through the traditional displacement experiments due to limitations in experimental operations and measurement accu...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of Hydrogeology & Engineering Geology
2024-11-01
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| Series: | Shuiwen dizhi gongcheng dizhi |
| Subjects: | |
| Online Access: | https://www.swdzgcdz.com/en/article/doi/10.16030/j.cnki.issn.1000-3665.202401015 |
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| Summary: | The hydraulic conductivity of a quasi-saturated aquifer decreases with the increase of air-trapped saturation, but it is difficult to obtain a continuous data on air-trapped saturation through the traditional displacement experiments due to limitations in experimental operations and measurement accuracy. It limits the accurate characterization of the relationship between small air-trapped saturation and the corresponding quasi-saturated hydraulic conductivity. This study designed an oxygen-trapped dissolution experiment in quasi-saturated fine sands media, instead of air-trapped, in which the soluble oxygen in water and the corresponding hydraulic conductivity can be accurately measured. Then a large amount of continuous data on air-trapped saturation and its quasi-saturated hydraulic conductivity were obtained. The experimental results show that when the air-trapped saturation is less than 5%, trapped gas may enter the ineffective pores and thus has a little effect on the value of the hydraulic conductivity. However, when the trapped gas saturation is between 5%－6%, it forms a pore throat block effect, which intensifies the influence on the hydraulic conductivity. Furthermore, a new model, i.e., van Genuchten model, was constructed to predict the quasi-saturated hydraulic conductivity. This model overcomes the shortcomings of the traditional power-law model and well characterized the feature that the small air-trapped saturation has little effect on the hydraulic conductivity. At high air-trapped saturation, the performance of van Genuchten model is comparable to the traditional model. The proposed model in this study can provide foundation for studying quasi-saturated water flow and solute transport. |
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| ISSN: | 1000-3665 |