Characterization of stony soils' hydraulic conductivity using laboratory and numerical experiments
Determining soil hydraulic properties is of major concern in various fields of study. Although stony soils are widespread across the globe, most studies deal with gravel-free soils, so that the literature describing the impact of stones on the hydraulic conductivity of a soil is still rather scarce....
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-08-01
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| Series: | SOIL |
| Online Access: | http://www.soil-journal.net/2/421/2016/soil-2-421-2016.pdf |
| Summary: | Determining soil hydraulic properties is of major concern in various fields
of study. Although stony soils are widespread across the globe, most studies
deal with gravel-free soils, so that the literature describing the impact of
stones on the hydraulic conductivity of a soil is still rather scarce. Most
frequently, models characterizing the saturated hydraulic conductivity of
stony soils assume that the only effect of rock fragments is to reduce the
volume available for water flow, and therefore they predict a decrease in
hydraulic conductivity with an increasing stoniness. The objective of this
study is to assess the effect of rock fragments on the saturated and
unsaturated hydraulic conductivity. This was done by means of laboratory
experiments and numerical simulations involving different amounts and types
of coarse fragments. We compared our results with values predicted by the
aforementioned predictive models. Our study suggests that it might be ill-founded to consider that
stones only reduce the volume available for water flow.
We pointed out several factors of the saturated hydraulic conductivity of
stony soils that are not considered by these models. On the one hand, the shape and
the size of inclusions may substantially affect the hydraulic conductivity.
On the other hand, laboratory experiments show that an increasing stone
content can counteract and even overcome the effect of a reduced volume in
some cases: we observed an increase in saturated hydraulic conductivity with
volume of inclusions. These differences are mainly important near to
saturation. However, comparison of results from predictive models and our
experiments in unsaturated conditions shows that models and data agree on a
decrease in hydraulic conductivity with stone content, even though the
experimental conditions did not allow testing for stone contents higher than 20 %. |
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| ISSN: | 2199-3971 2199-398X |