E3S Web Conf.
Volume 195, 20204th European Conference on Unsaturated Soils (E-UNSAT 2020)
|Number of page(s)||5|
|Section||Experimental Evidence and Techniques|
|Published online||16 October 2020|
Water retention and transfer properties of a Green roof volcanic substrate
1 Ecole des Ponts ParisTech, Navier/CERMES, F 77455 Marne la Vallée, France
2 Ecole des Ponts ParisTech, HMCo, F 77455 Marne la Vallée, France
* Corresponding author: firstname.lastname@example.org
The water retention curve and the hydraulic conductivity function of a volcanic coarse granular material used as a substrate in an urban green roof in the Paris area was carried out on a newly developed device, in which low suctions were controlled. In the same cell, a hanging column system was used for controlling smaller suctions (up to 32 kPa) and the axis translation technique for larger suctions (up to 50 kPa). Water exchanges were monitored in connected tubes by using a high accuracy differential pressure transducer. The step changes in suction were also used to determine the hydraulic conductivity function by means of Gardner’s method, accounting for the impedance effects due to the high air entry value ceramic porous disk with Kunze and Kirkham’s method. van Genuchten and Brooks and Corey models were used for the water retention curve, but the hydraulic conductivity functions derived from these expressions appeared to lead to a significant under-estimation, confirming the need of operational and simple device for the experimental determination of the hydraulic conductivity function.
© The Authors, published by EDP Sciences 2020
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