Mass-stabilization quality control methods

This article presents applicability of sounding and sampling methods for quality assurance (QA) of mass stabilized soil, and the soil parameters that can be determined using these methods. The target is also to provide recommendations and background information concerning the QA methods utilized for mass stabilized soil. During shallow depth mass stabilization binder is mixed into soft soil using a mixing tool. QC starts during the mass stabilization (deep soil mixing) work process in order to optimize the stabilization work and continues as QA after the stabilization work to verify the strength increase and the homogeneity of stabilized soil. Stabilized soil differs from virgin soil and thus the modified QA sounding methods, large quantity of soundings and statistical analyzing of the results are needed. The QA methods utilized vary according to the site and the construction goals. On the basis of the experience during last decades it can be stated that quite a many QA methods are suitable for investigation of the geotechnical parameters of stabilized soil as discrete tests but only a few of the methods are suitable for day-to-day QA of production mass stabilization.