Use of SDMT testing for measuring soil densification by ground improvement in Christchurch, New Zealand

The paper illustrates, and comments on, the results of seismic dilatometer (SDMT) obtained in Christchurch, New Zealand, in combination with the results of piezocone penetration tests (CPTu). SDMTs were carried out at sites close to the Avon River in treated soils and in adjacent natural soils, in order to evaluate the effectiveness of the different ground improvement tecniques, including Rammed Aggregate Piers (RAP) and Low Mobility Grout injection (LMG). The results confirm that the DMT, as well as CPT, is sensitive to changes of stresses/density in sands and silty sands, and is therefore well suited to detecting improvements in these soils, while VS provides less evident results.