ABSTRACT
Multiple interbedded fine-grained layers in a sand deposit have a “smoothing” effect on the measured tip resistance (qc ) from the cone penetrometer test (CPT). This can result in an underestimation of the predicted liquefaction resistance of the sand layers. Herein, the efficacies of two multiple-thin-layer correction procedures are evaluated using published calibration chamber test data. The results highlight limitations of the assessed procedures for profiles with layers less than 40 mm thick. A new approach to estimate the “true” qc (i.e., values that would be measured in a stratum absent of multiple thin-layer effects) from measured qc is explored. The proposed numerical optimization algorithm searches for “true” soil profiles with a finite number of layers. We compare two versions of the algorithm that numerically optimize different functions, one of which uses a logarithm to refine fine-scale details, but which requires longer calculation times to yield improved corrected qc profiles.
