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Soil reinforcement includes a set of techniques in order to improve its mechanical or physical properties, by the establishment of inclusions working on traction, compression or bending. Among these techniques are nailing, tie rods, micro piles, bored piles, ballasted columns. Slope stability can be improved with different ways using soil improvement techniques or by installing supporting structures such as retaining walls or piles. The first solution leads to the reduction of forces that cause sliding; the other solutions generally lead to the increase of resistance forces. The present work is concerned with the sensitivity of the deformations of contiguous drilled pile walls reinforced by tie rods associated with the models of soil behaviour. The analysis is done on the metro station of Algiers Line 1, Extension C-Hai el Badr-Ain-Naadja (station of Ain-Naadja). The obtained results by a numerical simulation in 3D, deformations at the level of the piles or displacements, as well as the efforts of extensions at the level of the tie rods are compared with the measurements in situ taken in very particular points either at the level of the tie rods or by inclinometers at the level of the piles. [ABSTRACT FROM AUTHOR]

Extracting built-up areas from remote sensing data like Landsat 8 satellite is a challenge. We have investigated it by proposing a new index referred as built-up land features extraction index (BLFEI). The BLFEI index takes advantage of its simplicity and good separability between the four major component of urban system, namely built-up, barren, vegetation and water. The histogram overlap method and the spectral discrimination index (SDI) are used to study separability. BLFEI index uses the two bands of infrared shortwaves, the red and green bands of the visible spectrum. OLI imagery of Algiers, Algeria, was used to extract built-up areas through BLFEI and some new previously developed built-up indices used for comparison. The water areas are masked out leading to Otsu's thresholding algorithm to automatically find the optimal value for extracting built-up land from waterless regions. BLFEI, the new index improved the separability by 25% and the accuracy by 5%. [ABSTRACT FROM AUTHOR]