Dynamic Undrained Shear Strength Behavior of Bentonite–Grouted Sand

In this paper the results of dynamic and static triaxial tests on uniformed graded sand of Firoozkooh (131) has been tested and examined, which has been injected by bentonite slurry in different concentrations. The bentonite slurry inside the soil texture, can lead to changes the mechanic and hydraulic properties of soil. The results show that the bentonite being in sand leads to increase the liquefaction resistance. It was seen that when the slurry concentration is less than 7.5% it cannot have a significant impact on the liquefaction resistance, but by increasing the concentration of the slurry to 10%, liquefaction resistance increase effectively. The severity of liquefaction resistance changes for samples with low slurry concentrations was slow, and with increasing of slurry concentration was drastic. In addition it was observed that with increasing the concentration of slurry, the maximum dynamic modulus of elasticity increases. Due to obtained results, the soil liquefaction resistance through time and due to thixotropic process of bentonite, increases faster but after a specified period of time the rate of increase was slower. The static triaxial tests on injected bentonite samples were also compatible with dynamic testing results.