VALIDATION OF HYPERBOLIC METHOD FOR SETTLEMENT IN CLAYS WITH VERTICAL DRAINS

概要

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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 U_<60> and U_<90> points for the combined flow problem. Based on detailed parametric studies, it is shown that the slope (α) of the first linear segments between U_<60> and U_<90> for the theoretical hyperbolic plots (T_υ/U vs T_υ) 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 (c_h/c_υ). The slope S_i of the first linear segment of the field hyperbolic plot and the slope α can be used to identify the U_<60> and U_<90> points on the field settlement plot. These are used to estimate the total primary settlement from field settlement data as either α/S_i, δ_<60>/0.6 or δ_<90>/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.
社団法人地盤工学会の論文
1995-03-15