1. Monotonic undrained simple shear tests performed on horizontally oriented samples of an estuarine clay-silt indicated that significantly higher strengths can develop when shearing in a direction orthogonal to the bedding plane (as in the case of a axially loaded vertical pile) rather than parallel to the bedding plane. 2. There are clear parallels between the displacement response of piles subjected to undrained cyclic tension loading and the shear strain development observed in undrained cyclic simple shear (CSS) tests. 3. Cyclic tension pile tests indicated that the initiation of a rapid accumulation of pile head displacement with N only began when the applied peak cyclic tension load was close or equivalent to the piles' (slow) static tension capacity. 4. The results of CSS tests on pre-sheared soil are directly applicable to pile response to cycling loading and may be used, at least in a qualitative way, to assess the displacement performance of piles subjected to axial cyclic loading. 5. Static capacity changes take place in addition to the described permanent displacement accumulation.
展开▼
