Cα/Cc Concept and K0 During Secondary Compression

The Cα/Cc concept, which completely defines secondary compression behavior of any one soil in terms of a constant Cα/Cc and the EOP e‐log συ′, is a powerful practical tool for settlement analysis and interpretation of data from load‐controlled and deformation‐controlled consolidation tests. The correct procedure for evaluating Cα/Cc for any soil is described. The Cα/Cc concept was used to obtain an expression for the behavior of the coefficient of earth pressure at rest, K0, during secondary compression. This approach predicts an increase in K0 during secondary compression. This approach also predicts that the K0=1 condition will not be reached during the typical geologic age of soft clay deposits. Laboratory measurements on the behavior of K0, including during secondary compression, are presented for four soft clays. The proposed approach also provides an estimate of in situ K0 in soft clay deposits. Two alternative laboratory procedures were used to determine in situ K0 for four soft clays. These values compare well with the predictions.