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The pre-consolidation pressure of a laterite soil

  • Malomo S. 
  • Ogusanwo O. 
Article

Abstract

The pre-consolidation pressure of a soil is often determined in the oedometer using the Casagrande method. Recently, the trend has been to carry out this determination using the ‘Constrained Modulus’ method. The relationships between the constrained moduli, the normal pressures and the pre-consolidation pressures of temperate-zone soils have also been established.

These relationships are investigated for an undisturbed tropical soil—an amphibolite derived laterite soil in the fixed ring oedometer. The pre-consolidation pressures as well as the over-consolidation ratios thus obtained are evaluated along with those obtained using the Casagrande method.

The values of the pre-consolidation pressures obtained using the Casagrande and the ‘Constrained Modulus’ methods gave means of 3,8×102 and 3,5×102 KN/m2 respectively. The respective coefficients of variation are 0.40 and 0.58. A test of the significance of the difference of the means shows no significance at the 1% level on the Student-t distribution. The constrained modulus method is however recommended for determination of pre-consolidation pressures of laterite soils in view of its advantages over the other method.

Keywords

Cementation Laterite Soil Consolidation Test Consolidation Pressure Preconsolidation Pressure 

La pression de pre-consolidation d'un sol lateritique

Résumé

La pression de pré-consolidation d'un sol est souvent déterminée à l'aide de l'oedomètre en se servant de la méthode de Casagrande. Acutuellement, on a tendance de se servir de la méthode du “module confiné”. Les relations entre les modules confinés, les pressions normales et les pressions de pré-consolidation des sols tempérés on été également établies.

Ces relations sont étudiées en les appliquant à un sol tropical non remanié, c'est-à-dire un sol lateritique dérivé d'une amphibolite, à l'aide d'un oedomètre à anneau fixe. Les pressions de préconsolidation comme les rapports de sur-consolidation ainsi obtenus sont comparés à ceux obtenus en se servant de la méthode de Casagrande.

Les données pour les pressions de pré-consolidation obtenues avec les méthodes de Cassagrande et les méthodes du “module confiné” sont respectivement—3,8×102 et 3,5×102KN/m2. Les coefficients de variation sont respectivement 0,40 et 0,58. Le test sur la différence entre les moyennes, montre qu'elle n'est pas significative au niveau de 1%, en distribution de Student-t. La méthode du module confiné est recommandée pour la détermination des pressions de préconsolidation des sols latéritiques.

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References

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Copyright information

© International Association of Engineering Geology 1983

Authors and Affiliations

  • Malomo S. 
    • 1
  • Ogusanwo O. 
    • 1
  1. 1.Department of GeologyUniversity of IfeIle-IfeNigeria

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