Titre :
|
A multistep constant-head borehole test to determine field saturated hydraulic conductivity of layered soils
|
Auteurs :
|
J. Xiang ;
B. Scanlon ;
W. Mullican ;
AL Et
|
Type de document :
|
article/chapitre/communication
|
Année de publication :
|
1997
|
Format :
|
p. 45-57
|
Langues:
|
= Anglais
|
Catégories :
|
HYDROLOGIE ET HYDRAULIQUE
|
Mots-clés:
|
CONDUCTIVITE HYDRAULIQUE
;
MESURE
;
MILIEU NON SATURE
;
SIMULATION NUMERIQUE
;
MULTICOUCHE
|
Résumé :
|
Although most held soils are heterogeneous, existing analytical solutions to estimate field saturated hydraulic conductivity K-fs in unsaturated systems assume that the soil is homogeneous. To overcome the limitations of existing analytical solutions we propose a multistep constant head borehole test to evaluate the field saturated hydraulic conductivity of layered media. The field test consists of conducting constant head borehole tests at different depths that correspond to the different layers in the soil. Measurements of water level and the stable flow rate are then used to compute the hydraulic conductivity of each layer. Equations for evaluating the saturated conductivity of each layer are derived. To determine the how contribution of each layer, a new pressure solution is also presented. One of the assumptions of the proposed analytical solution is that the pressure gradient on the borehole wall of each layer is independent of the hydraulic conductivity of the layer. Comparison of analytical results with numerical simulation results show that this assumption is reasonable. The proposed analytical procedure can be used to calculate both the saturated and unsaturated how components.
|
Source :
|
Advances in water resources, vol.20, n°1
|