LAUSR

The main object of this research is the investigation of the behavior of clay-sand mixtures in undrained condition. For this purpose, the behavior of clay mixed with the different percentage of sand (i.e., 0%, 20%, 40%, and 60%) was studied by carrying out undrained triaxial tests on normally consolidated and overconsolidated specimens under different effective stresses. The results showed that sand inclusion up to 20–40% (depend on sand size) does not affect considerably the shear strength of the clay, but when the amount of sand is more than 40%, the shear strength raises 74 to 260%. Maximum pore water pressure at low confining pressures remains unchanged by changing sand content from 0 to 60%. At high confining stress, this parameter for specimens consists of 40% sand is higher than the corresponding values of the other ones. For overconsolidated specimens, irrespective of some exceptions, dependent on sand size, the values of shear strength improve 43 to 73% when sand content varies from 0 to 60%. In addition, deformation modulus of both normally consolidated and overconsolidated mixtures increases 9 to 136% by an increase in sand content from 0 to 40%, and, then, the values diminish rapidly by changing sand content from 40 to 60%.