Caractérisation et estimation du gonflement des argiles algériennes, cas des argiles de Médéa

Abstract

Résumé. Le matériau argileux, dur et cassant lorsqu'il est asséché, présente la particularité de voir sa consistance se modifier en fonction de sa teneur en eau. Un certain degré d'humidité peut le transformer en un matériau plastique et malléable. Ces modifications de consistance peuvent s'accompagner, en fonction de la structure particulière de certains minéraux argileux, de variations de volume plus ou moins conséquentes qui se manifestent soit sous forme d'une forte augmentation de volume (phénomène de gonflement) lorsque la teneur en eau augmente ou de rétrécissement (phénomène de retrait) en période de déficit pluviométrique marqué. Ce comportement est lié essentiellement à certains paramètres environnementaux de ces sols à l'exemple de la géologie et de la lithologie du site, du climat, etc. La prévision du potentiel de gonflement des sols est possible moyennant certaines méthodes empiriques basées sur des paramètres d'identification tels que la plasticité et la granulométrie déterminées lors des campagnes de reconnaissance. Une fois le caractère de gonflement pressenti dans la phase de reconnaissance préliminaire, une estimation de l'amplitude et de la pression de gonflement peut être établie à partir des corrélations, qui tendent à mettre en relation les paramètres de gonflement avec les paramètres géotechniques issus des essais d'identification. C'est dans cet aspect que s'inscrit cet article en traitant le cas d'un site algérien. Les résultats obtenus montrent une concordance entre les méthodes empiriques appliquées. Ces résultats sont aussi comparés avec ceux obtenus des essais de gonflement à l'oedométrique. L'évolution de la structure argileuse au cours de retraitgonflement est suivie dans l'objectif de comprendre le mécanisme de gonflement. Mots clés :Argiles gonflantes, identification, prévision, estimation, évolution de gonflement.Abstract. The clayey material hard and brittle when dry, presents the particularity of changing its consistence as a function of its water content. A certain percentage of moisture may transformed it into a plastic and manageable material. Depending on the particular structure of clay minerals, these modifications of consistence may be accompanied by more or less substantial volume variations, manifested, either, as a sharp increase of volume (swelling phenomenon) when the water content increases or shrinkage (shrinkage phenomenon) in period of marked rainfall. This behavior is essentially linked to some of environmental parameters of these soils, for example: the geology and lithology of the site, the climate, etc. The prediction of swelling potential of soil is possible with empirical methods that based on identification parameters, such as plasticity and particle size, determined during the reconnaissance campaigns. Once the character of the swelling sensed in preliminary recognition phase, an estimate of the amplitude and the pressure of swelling can be established by correlations that tend to link the swelling parameters with geotechnical parameters obtained from ...

Contribution to the characterization and valuation of a mixture of clay and dune sand for road construction

“…The importance of this phenomenon depends essentially on the quantity of swelling minerals. Its study is based on several aspects, namely: geological, climatological and geotechnical [7].Swelling potential classi cation was performed using indirect methods [8,9].The known stabilization products being dune sand, the solution obtained from the husk of the would reduce the swelling of clay soils [10].The stabilization of clay soils, and to extract from scienti c work the correlations established between the various geotechnical, physical, chemical, and mechanical parameters, determined from direct and indirect characterization tests [11][12][13].Geotechnical road tests are regulated by several standards which are essentially based on mechanical parameters to assess the compliance of the use of a material [14].In the particular case of ne clay soils,different identi cation parameters sometimes give results that do not ultimately allow an unequivocal decision to be made on the swelling nature of the soils [15].Improving soil properties, also called soil treatment or stabilization, is a technique introduced many years ago with the main purpose of making soils capable of satisfying clay soils [16].This treatment is often carried out to increase the strength, reduce or increase the permeability as well as to decrease the compressibility and minimize the sensitivity of the ne soil to variations in water content [17].For this purpose, it is necessary to use the other exterior material to improve the geotechnical performance of the site. Several studies have been carried out on the phenomena related to this type of soil [18].…”

Optimization and valorization of a clay and dune sand mixture for use in road construction

“…The extent of this phenomenon primarily depends on the amount of swelling minerals present and is studied from geological, climatological, and geotechnical aspects [11]. This article presents an estimation study of clay soils suspected of swelling in the Ouazzane region, including physical, chemical, and mechanical tests conducted on intact and remolded samples [12]. Indirect methods were used to classify the swelling potential [13].…”