Estimating hydraulic conductivity of naturally sedimented clays using compression curves

This study aims at establishing the hydraulic conductivity-effective vertical stress-void ratio interrelations for naturally sedimented clays under one-dimensional condition. The roles of soil structure developed during the depositional and the post-depositional processes in both the relationships of hydraulic conductivity versus effective vertical stress and void ratio versus effective vertical stress are investigated. It is found that the soil structure effect on the hydraulic conductivity-effective vertical stress curves can be attributed to that on the compression curves. The effect of initially deposited state on the hydraulic conductivity is also linked with that on the void ratio for naturally sedimented clays under the same values of effective vertical stress. The investigations indicate that the interrelation between hydraulic conductivity and compressibility is independent of initial state. That is, the hydraulic conductivity-void ratio relationship of naturally sedimented clays is independent of soil structure and initial state. Such a relationship is found to be a function of void ratio at liquid limit. Consequently, the hydraulic conductivity can be estimated based on the hydraulic conductivity-void ratio database established for naturally sedimented clays with a wide spectrum of void ratio at liquid limit. An empirical way of determining hydraulic conductivity is also proposed for naturally sedimented clays. A series of one-dimensional incremental load consolidation and hydraulic conductivity tests were performed. These data together with those compiled from the literature are used for investigating the accuracy of the suggested methods of determining hydraulic conductivity.