Model footing load tests on soft rocks

This paper summarizes the results of model footing load tests on soft Calcarenite rock. To perform the experiments, a new testing device was specifically designed, and its conception and features are described in details. The centered loading tests exhibited the typical bilinear shape of the load-settlement curve since a marked change of stiffness occurs as a consequence of collapse of the lightly cemented sand structure. These tests reveal that the failure mechanism is punching shear, and it is bounded in a small region beneath the loaded area. Further tests investigated the influence of the displacement rate and footing size effect, together with tests that show a moisture-induced loss of strength. The eccentric loading tests point out the role played by the interacting external loads, and the coupling between vertical displacement and footing rotation. The overall tests allow the interaction diagram of the soil-foundation system to be derived. Copyright © 2009 by ASTM International.