Pore pressure measurements during rapid pile load tests in a geotechnical centrifuge

The generation of excess pore pressures and subsequent consolidation are of importance when determining static pile capacity from a rapid pile load test. Tests in a geotechnical centrifuge offer insight into the physical background of the phenomena. Centrifuge tests (scale 1:40) have been performed. Four static tests were carried out on a pile that was installed by inserting it into sand, alternating with three sets of four rapid load tests. The rapid load tests differed with respect to loading rate and amplitude of loading. The tests were repeated using several sand densities and two different pore fluid viscosities. The tests give insight into the importance of pore water pressure when interpreting rapid load tests. The rate effects for the bearing capacity in sand under rapid load tests are mainly determined by how slowly the generated pore pressures dissipate.