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Microstructural investigation on laterite soils

  • S. Malomo
Article

Abstract

Considerable researches have been carried out to demonstrate the importante of microstructure in the interpretation of engineering behaviour of soils. Instances where the investigations are on laterite soils are however scanty in literature.

The microstructure of laterite soils obtained from Eastern Nigeria and North-East Brazil, have been examined with the aid of optical and scanning electron microscopes.

Investigations reveal the development of the well-known concretionary structure in laterite as a stage by stage process involving the accumulation of sesquioxides. The sesquioxides are accumulated initially as amorphous implantations in the pore spaces, the crystallisation of which leads to bonding of soil elements and formation of concretionary structure. The nature of cementation in the concretionary structure determines the resistance to degradation of the soils grains. The resistance to degradation would in turn influence the engineering behaviour.

Keywords

Iron Oxide Nigeria Goethite Cementation Laterite Soil 

Étude de la microstructure de sols latéritiques

Résumé

De nombreuses études ont été entreprises pour mettre en évidence l'importance de la microstructure pour l'interprétation du comportement géotechnique des sols. Les exemples concernant les laterites sont cependant peu répandus dans la littérature.

La microstructure de sols latéritiques provenant de l'Est du Nigéria et du Nord-Est du Brésil a été étudiée à l'aide des microscopes optique et à balayage.

Les études ont mis en évidence le développement de la structure concrétionnée bien connue dans les latérites, processus progressant par étapes et comportant l'accumulation de sesquioxydes. Ces derniers s'accumulent d'abord en amas amorphes de remplissage de pores, et leur cristallisation conduit à former des liaisons entre les éléments du sol et à mettre en place la structure concrétionnée. La nature de la cimentation dans cette structure détermine la résistance des soils à la dégradation, et donc leur comportement géotechnique global.

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Copyright information

© International Association of Engineering Geology 1989

Authors and Affiliations

  • S. Malomo
    • 1
  1. 1.Commonwealth Science CouncilLondonUK

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