Evaluation of ground densification using spectral analysis of surface waves (SASW) and resonant column (RC) tests

In order to assess the quality and depth of ground densification due to compaction, standard and (or) cone penetration tests are often performed before and after compaction. Both methods are intrusive and one-location tests and require a substantial amount of time to evaluate a large area, and evaluation quality is quite dependent on the operation technique and soil type. In this paper, the quality and extent of ground densification by compaction were evaluated using the results from in situ spectral analysis of surface waves (SASW) tests and laboratory resonant column (RC) tests. The SASW test was used to determine the shear wave velocity profiles before and after compaction, and the RC test was adopted to determine the correlation between the normalized shear wave velocity and density of the site, which is almost independent of confinement. Testing and data-reduction procedures of both tests were discussed, and a simplified procedure for evaluating ground densification was proposed by effectively combining in situ shear wave velocity profiles determined by SASW tests with the correlation between normalized shear wave velocity and density determined by RC tests. Finally, the feasibility of the proposed method was verified by performing field studies at the Inchon International Airport project. Field densities determined by the proposed method matched well with those determined by sand cone tests.