Volume 26, Issue 3 (September 2003)
Anisotropic Consolidation Behavior of Soft Bangkok Clay
The anisotropic consolidation behavior of soft Bangkok clay is investigated by means of constant rate of strain consolidation tests with vertical and radial drainage conditions. Conventional oedometer tests were performed to verify the results of constant rate of strain consolidation tests in the vertical flow condition. Better-defined compression curves were obtained from the CRS tests, resulting in better estimation of preconsolidation pressure. A new method of determining the preconsolidation pressure based on the pore pressure ratio gave values close to those obtained from the Casagrande construction of compression curves. The results of CRS tests under different drainage conditions indicated that soft Bangkok clay is slightly anisotropic, with the ratio of coefficients of consolidation and permeability in the horizontal to vertical directions of about unity at in-situ stress. The difference increases with increasing stress due to stress-induced anisotropy of the soil.