Structural cutting of a region showing various compound tectonic deformations (example of Bouficha–Grombalia region)

Bouficha–Grombalia region shows complex tectonic deformations and is affected by faults and folds of different geometry. A structural study has allowed to determine that Bouficha–Grombalia region is affected by significant faults of EW, NE-SW and NW-SE directions. These faults divide Bouficha–Grombalia region into several compartments. We distinguish three important structures whose first is in the SW which corresponds to Zaghouan–Bouficha trough. The second structure is situated in the NE, which corresponds to the Grombalia trough. The third structure occupies a central position; it consists in the Bouficha–Grombalia high structure. The last structure is composed by three blocks. Each block is characterised by particular folds geometry. These structures were outlined at least from middle Miocene, and they have undergone the effect of subsequent compressive tectonic events which have led to folds building above or counter the pre-existing NE-SW faults.     

Caractérisation géométrique et cinématique des structures liées aux phases compressives de l'Éocène au Quaternaire inférieur en Tunisie : exemple de la Tunisie nord-orientale

During Eocene to Early Quaternary period, three compressive tectonic phases are recognized in Northeast Tunisia: a NW–SE to north–south phase during the Late Eocene, a N120-to-N140 phase in the Late Miocene, and a NW–SE to north–south phase in the Plio-Early Quaternary. The first Eocene phase has built NE–SW folds and remobilised east–west-to-N120 and NE–SW faults with a reverse component. The second Miocene phase is characterized by east–west-to-N120 faults with a normal component and NE–SW folds. The third phase occurred during the Plio-Early Quaternary has edified NE–SW folds associated with east–west-to-N120 dextral reverse strike-slip faults and NE–SW faults with a reverse component. To cite this article: H. Mzali, H. Zouari, C. R. Geoscience 338 (2006).     

Evaporation,shrinkage and intrinsic permeability of unsaturated clayey soil: analytical modelling versus experimental data

This paper presents the experimental study conducted on a clayey soil originating from the region of Béja, north-west of Tunisia. The evaporation, shrinkage and permeability behaviours were studied. The Soil Water Retention Curve (SWRC) was determined from the slurry state to dry state, under the desiccation path (called initial drying curve). The Crack Intensity Factor (CIF), settlement and void ratio were also studied to characterise the shrinkage phenomenon during desiccation. Moisture content (ω), saturation degree (S_r) and evaporation rate (R_e) evolutions during desiccation path were also presented. This type of slurry clay presents three stages during the desiccation process (pendular, funicular and capillary regimes). During desiccation process, the evaporation rate presents a linear relationship as a saturation degree function. Furthermore, the evaporation rate versus suction presents two phases: quasi-saturated and unsaturated states. This paper introduces a study of the hygroscopic and mechanical parameters naturally modified during a desiccation process and proposes some analytical models to describe clay behaviour. Using these parameters, we can determine the intrinsic permeability during the desiccation process.