Multivariate analysis of a grouted sand with colloidal silica at different dilution stages

Grouting is one of the most known ground improvement technique to increase strength and/or stiffness of soils. Among all, permeation grouting uses grout to fill up soil voids, without altering the stress state in the soils by injecting it into voids as solutions. This work illustrates laboratory results, in terms hydro-mechanical parameters, of a fine-grained sand grouted under low pressure with a colloidal silica diluted at different solid content (i. e., 40%, 30% and 20%). Hydro-mechanical properties of the soil include unconfined compressive strength at different curing days, hydraulic conductivity, effective cohesion, peak and residual friction angles. Uncertainties associated to geotechnical parameters variability and their dependences are exploited and quantified by means of a multivariate probabilistic approach built on regular vine copula scheme. A Bayesian Information Criterion is applied to select the best fitted dependence structure to be further employed within a reliability design method.