Caractérisation minéralogique,physiqie et cartographie des sols gonflants dans le bassin de Tébessa, Impact sur le plan d'aménagement.

Abstract

Prediction of soil swelling characteristics and accurate quality estimation can be of great consideration and contribution regarding site stability. Any concerned investigation is correspondingly an advanced priority for project realization. Related inquiries allow potential reduction concerning financial and technical charges damage prior to any urban development. The determination of soil characteristics lead for a best recognition, and allow for the best choice of foundation type adopted for each site. Thus, in any urban case study, much gain can be made by team work recording and surveying the related data. In the considered city of El Kouif, located at Tebessa in Algeria, several buildings have been built mainly on expansive soils. Observations indicate different severe damages which were caused mostly in the nearby structures. These damages are characterized by deflection and failure of walls. Lateral and vertical displacements evidences support the presence of shear movements and subsidence. The scale up of these movements occurrence can reach millimetric shifting dimension. Laboratory analysis was executed on soil study, results and discussion of those analysis show that the soil study are characterized by a large range of geotechnical parameters. Geotechnical classification shows that the soils are classified in the high to very high domain of swelling. Ground and subsurface risk activity affecting El Kouif city site are also related to the presence of destructive chemical components such as sulfates. The chemical by fluorescence, and mineralogical analysis (XRD), emphasizing, at the same time, the high percentage of sulfate with the clay minerals (smectite). The sulfate occurrence is illustrated through generally gypsum minerals concentration present in the concerned soil. Source for these chemical products expansion might be associated to historical event: the city of El Kouif was the field of phosphates mining area in addition to established phosphate extraction plant. Thus, determination of soil characteristics and involvement of chemical components turn out to be the main objectives in this investigation.