抄録
In this paper, the hyperbolic fitting method is extended to the case of consolidation with combined vertical and radial flow, which occurs when vertical drains are used to accelerate consolidation in clayey soils. Theoretical results indicate that the hyperbolic plots are linear between the U60 and U90 points for the combined flow problem. Based on detailed parametric studies, it is shown that the slope (α) of the first linear segments between U60 and U90 for the theoretical hyperbolic plots (Tυ/U vs Tυ) depends only on three non-dimensional parameters. These are the drain spacing ratio (n), the drainage path ratio (H/D), and the consolidation coefficient ratio (ch/cυ). The slope Si of the first linear segment of the field hyperbolic plot and the slope α can be used to identify the U60 and U90 points on the field settlement plot. These are used to estimate the total primary settlement from field settlement data as either α/Si, δ60/0.6 or δ90/0.9. In order to validate this approach for estimating total primary settlement for consolidation of clays with vertical drains, a controlled laboratory experiment using a flexible fibre drain in a clay cylinder, and several well documented case histories were examined. Estimates using the proposed hyperbolic method agree very well with actual settlements, thus, validating the method for field applications.
