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Accueil du site → Doctorat → Royaume-Uni → 1994 → Mole drainage studies in irrigated clay soils of The Gharb, Morocco

Cranfield University (1994)

Mole drainage studies in irrigated clay soils of The Gharb, Morocco

Elmessaoudi, M

Titre : Mole drainage studies in irrigated clay soils of The Gharb, Morocco

Etude du drainage de digue sur les sols calcaires irrigués du Ghrab, Maroc

Auteur : Elmessaoudi, M

Université de soutenance : Cranfield University

Grade : Doctor of Philosophy (PhD) 1994

This is a study of the mole drainage technique on swelling (cracking) clay soils of arid and semi arid irrigated areas. Mole drainage field trials were carried out on the vertisol clays of the Gharb irrigation area in Morocco. The investigations covered three aspects : Soil suitability for mole drainage ; machine design and methods of installation ; and, mole drainage functioning and installation practice under different irrigation situations.Two of the major soils (Tirs and Dehs) were subject to mole drainage suitability tests. Mole channels were stable on the Tirs soil and resisted up to five days ponding. The Dehs soil was found not to be suitable for mole drainage as on these soils mole channels collapsed within a few hours due to dispersion and slaking. The soil properties which were determined to be responsible for these differences were : the soil plasticity and water stability of the aggregates. Plasticity Index at moling depth is 35.91% for the Tirs soil and 22.51% for the Dehs soil. In relation to water stable aggregates, the stability index (SI) and mean weight diameter (MWD) were equal to 64.4 and 107.9 for Tirs respectively and 3.7 and 27.4 for Dehs respectively.Two mole plough designs were used : combination 1 with a leg thickness of 25 mm, foot diameter of 76.2 mm and expander diameter of 101.6 mm ; and, combination 2 with leg thickness of 12.5 mm, foot diameter for 50.4 mm and expander diameter of 88.9 mm. Methods for sealing the fissures consisted of disturbing the leg induced fissures using a trailed wedge attached to the leg at different depths followed by compacting the soil over the leg slit using tractor wheeling.

Cette étude porte sur la technique de drainage de digue sur des sols calcaire qui peuvent gonflés (et craqués) dans des zones arides et semi-arides. Les tests ont été faits sur deux plans de digues de labourage de la zone d’irrigation du Gharb au Maroc. Ont été investigués : la convenance du sol, le fonctionnement de drainage du sol et la pratique de l’installation dans différentes situations d’irrigation et plan de machines et méthodes d’installation.

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