Experimental Study on the Effect of Evaporation and Transpiration Action on a New Geotextiles ’ Drainage Efficiency

Abstract

Compared with conventional geotextiles, the new geotextile is a geomaterial woven with a hydrophilic nylon fabric that has a high drainage performance in an unsaturated environment; however, the drainage efficiency is affected by the installation method, precipitation, temperature, relative humidity, etc. Currently, certain studies have been conducted on the influence of installation method and precipitation on drainage efficiency; however, there is a lack of systematic research on the influence of evaporation and transpiration on drainage efficiency. In view of this limitation, based on the drainage test results of sand-free drainage and the new geotextile horizontal laying (drainage end extends to the air) and by setting a layer of new geotextile in the sand, the comparative drainage tests were first carried out under different laying methods (drainage end did not expose to air, so non evaporation). Second, by setting a layer of new geotextile in the sand, the comparative drainage tests were carried out between the drainage end exposed to the air (evaporation) and the drainage end passed through the grass-vegetated soil (transpiration) to explore the influence of evaporation and transpiration on the wetting front and the moisture content (volumetric and gravimetric). The results show that after installing a layer of new geotextile in the sand, although the drainage path was increased, the drainage end of the new geotextile was not exposed to air and then no evaporation occurred. In addition, there was no humidity difference on the new geotextile, and no suction difference was generated; therefore, the moisture movement was affected only by gravity, and its drainage efficiency was close to that of sand free drainage. Conversely, when the moisture movement was affected by the dual action of gravity and suction, more water would be drained out. The dewatering efficiency of the new geotextiles under the condition of evaporation was 1.25 times higher than that of the nonevaporation, and the evaporation exerted a much greater effect on dewatering than that of the installation method. Evaporation is equivalent to the natural "water pump", and the new geotextile acts as a drainage pipe. If the dewatering time is long enough, water could be consistently reduced by this new geotextile. The drainage end of the new geotextile should be extended into the air for evaporation to maximize drainage efficiency. If the dewatering geomaterial has a low drainage performance in the unsaturated environment, it would not only fail to drain but also block water migration, leading to siltation and a rise in the water table, which would have a negative impact. Transpiration and soil evaporation increased the dewatering efficiency of the new geotextile. However, the effect was less than that of evaporation. The research results could provide a reference for the design and construction of this new geotextile.

Department(s)

Civil, Architectural and Environmental Engineering

Keywords and Phrases

dewatering efficiency; evaporation and transpiration action; moisture content; new geotextile; test; wetting front

International Standard Serial Number (ISSN)

1672-7029

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Tongfang CNKI (Beijing) Technology Co., All rights reserved.

Publication Date

01 Jan 2024

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