PROJECT VELACS - CONTROL TEST-RESULTS

Results presented in this paper represent the first part of research produced by the Verification of Liquefaction Analysis by Centrifuge Studies (VELACS), a cooperative research effort involving eight universities. Ultimately, the objective of the project is to perform a series of dynamic centrifuge model tests on a variety of different soil models to study the mechanisms of liquefaction-induced failure and to use the results of these tests to verify various numerical procedures used in the analysis of liquefaction problems. However, prior to completing this final part of the project, a series of model tests was run by each of the eight universities to evaluate the dependence of centrifuge test results on the testing apparatus and test team; these results are presented here. Each university performed one model test using a standard model box; soil- and test-preparation technique; soil configuration: and input earthquake motion. Model accelerations, pore-water pressures, and surface settlements were measured during the eight tests and are compared in this paper. The test results help to define a general mechanism of liquefaction and show that similar results can be obtained when testing standard models at different centrifuge facilities. Although some scatter was observed, the results are sufficiently close to endorse their use in analysis validation exercises.