New method for determining the permeability function parameters of soft soils considering synchronous sedimentation and consolidation

Abstract

The measurement or estimation of the permeability of soft sediments remains a difficult albeit necessary task for several geotechnical applications, such as land reclamation and tailings management. This note presents a new method for determining the two parameters (the multiplier and power) of the power permeability function for high water content sediments, using settlement data from a column experiment, where sedimentation and consolidation occur synchronously. The proposed method stems from the distinct effects of the multiplier and power on the geometric features of numerically predicted settlement curves in the height versus log-time plane. The predicted settlement curves shape is multiplier-independent but controlled by the power; whilst, for a prescribed power, the position of settlement curve depends on the multiplier and can be shifted according to a change in the multiplier without using additional simulation. These effects were recently observed to apply to consolidation analysis only (i.e. without sedimentation), but here are shown to be more general. Further, it is newly shown that the mathematical variance of logarithms of times at a set of random points on the predicted settlement curve correlates very well with the power value. Together, these correlations lead to the development of a new method for calibrating the power and then multiplier that is both accurate and inexpensive (computationally and experimentally), as demonstrated using a well-known case study.