3D Consolidation of Tunis Soft Clay Improved by Geodrains

Abstract

Abstract This paper presents an experimental study carried out on undisturbed cored samples of Tunis soft soil extracted at 17.25 m depth at the lagoon of Sejoumi. Three series of oedometer tests were performed: the first one was a standard test on Tunis soft soil, the second one was performed on the same soil improved by a prefabricated vertical drain Mebradrain 88 (Mb88) type during which vertical drainage was prevented. The third series comprised similar tests to those of series two, during which horizontal and vertical drainage were allowed. The assessment of Carillo's theory was studied by quantifying the effect of radial and vertical consolidation from the observed global degree of consolidation of improved Tunis soft soil specimens by geodrains. The rate in decrease of coefficients cr and kr was greater than that recorded for coefficients cv and kr, respectively. Using the Carillo's theory, a lower degree of consolidation which starts from 10 % is obtained; however, when using simple approximate methods by considering recorded measures from series 3, higher degrees of consolidation starting from 70 % were obtained.