Tests on Model Instrumented Piles in Calcareous Soil

摘要

The paper describes the results of tests on model piles jacked into beds of reconstituted marine calcareous sediments. The behavior of a single pile is examined during installation, under static loading and under cyclic loading (both load-controlled and displacement-controlled). It is found that significant residual stresses exist in the pile after installation. A low skin friction is developed along the pile shaft, primarily due to the reduction of lateral stress which appears to occur during installation of the pile. Cyclic loading generally leads to a further reduction in skin friction, this reduction being a function of the cyclic displacement which the pile undergoes, rather than the cyclic load level. Comparisons are also made with the data obtained from previous tests on small model piles installed into the soil prior to consolidation of the soil bed. These comparisons show the importance of the in-situ lateral stress on the skin friction developed under static loading, but suggest that cyclic degradation is not seriously influenced by this factor.