economic benefits, the dark point of the wooden bridge technology is that it uses a raw material often worldwide contested. The heavy deforestation threatens the natural and physical environments [ 4 , 5 , 6 , 7 , 8 , 9 ]. Nobody knows exactly how much of the forests have already been destroyed, but many scientists around the world have proved that ground movements destroy a huge area of forests [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Drought and climate changes also contribute to their degradation [ 18 , 19 , 20 ]. In addition of the conversion of
Soumia Bellil, Khelifa Abbeche and Ouassila Bahloul
agglomeration of clay minerals with strong connectivities.
The EDS analysis shows that the sample is mainly a clay constituted of quartz silicates (Si), kaolinite (Al), iron oxide (Fe), carbonates (C), muscovite (KAl 2 ) and feldspar (K). These elements are attributed by the sand mixture, which is a quartzous discharge with kaolin, a high content of quartz (45.0%) and pure kaolinite (23.0%).
5.2 Microanalysis of treated soil
Figures 8c and d show a different structure compared to that of untreated soil (SNT). This difference can be attributed to the high bentonite
minimum global void ratio
Saturation and consolidation
The saturation of a sample represents an important stage in the experimental procedure. Indeed, its mechanical behaviour under undrained loading conditions depends heavily on the quality of its saturation. To obtain a maximum degree of saturation, the technique of carbon dioxide elaborated by Lade and Duncan (1973) was used. After taking necessary measurements, the samples have been first subjected to CO 2 for at least 30 min and then saturated by de-aired water. The evaluation of the saturation degree is