Evaluation of ground densification by dynamic compaction using SASW method

In order to evaluate the quality and depth of ground densification by dynamic compaction, standard penetration test and/or cone penetration test are frequently used in Korea. Because these evaluation techniques are intrusive and one-point tests, they require a substantial cost and time to evaluate a large area The Spectral-Analysis-of-Surface-Waves(SASW) method which is non-intrusive, has a great potential for rapid determination of effectiveness of ground improvement This method consists of making field measurements of surface wave velocity at various frequencies and determining shear wave velocity (V-s) profile through a inversion process. In this paper, the quality and extend of ground improvement by dynamic compaction was evaluated using SASW method. The shear wave velocity profiles were determined using SASW method before and after compactions. Resonant column (RC) tests were performed using reconstituted specimens of various densities and confinements, and shear wave velocity-void ratio-confinement (V-s-e-sigma(0)) relationship of the site was determined. The variations in void ratio with depth before and after dynamic compactions were evaluated by combining Vs profiles determined by SASW method with V-s-e-sigma(0) relationship determined by RC test Based on this study, the feasibility of using SASW method in the application of assessing the quality and depth of ground improvement was verified.