Mechanical Properties of a Sand Injected with a Colloidal Silica Binder with Different Dilution Grades

When it is desired to improve the strength and/or stiffness of a soil mass, grouting is applied. Stabilization of ground preparatory to tunneling, of an excavation pit and/or strengthening of dynamic machine foundations are examples of applications where the soil stiffness must be modified to minimize dynamic resonance concerns, to simply improve strength or decrease soil permeability. Colloidal silica in two different solid content values (i.e. at different dilution grades) was tested. A quartz sand was injected, and mechanical parameters such compressive strength, permeability values, and shear parameters were tested. A statistical analysis was also performed to understand whether the two solid content values may lead to different interpretation. Generally, the higher solid content binder provides higher mechanical response of the soil, however the decrease in soil permeability seems not to be connected to the dilution grade.