Use of PANDA Dynamic Cone Penetrometer for Site Investigation following Blast Liquefaction Testing

The PANDA variable energy dynamic cone penetrometer (DCP) is a mobile, instrumented DCP that enables rapid site investigation by one user. The PANDA was utilized in this study to measure cone tip resistance and develop site profiles at a blast liquefaction test site in Christchurch, New Zealand. The blast liquefaction testing occurred at two areas within the site. The first blast test was performed in soil that had been improved by resin-injection, whereas the second test was performed in untreated soil. Measurements were performed with the PANDA DCP prior to liquefaction and following liquefaction to evaluate changes in soil resistance as a result of liquefaction. Cone tip resistance profiles were developed for depths to 4.5 m and took approximately 30 min to complete. Results of the testing showed changes in cone tip resistance as a result of liquefaction for the untreated site where a decrease in resistance was observed. In addition, the PANDA DCP results were compared with cone penetration tests that were performed prior to liquefaction at both test areas and showed good agreement. The PANDA DCP was found to be a useful tool for site investigation following blast liquefaction tests as tests could be completed within 30 min of deployment in difficult to access areas.