THE MISCLASSIFICATION MATRIX - A TOOL FOR VALIDATING GEOTECHNICAL DATA

The misclassification matrix offers a powerful way to establish how re liable are the measurements of a geotechnical property and how well de fined are the categories in a classification scheme. Using soil streng th in a case history, poor agreement was generally observed between th e field description of soil consistency and the undrained shear streng th as measured in quick undrained triaxial tests on 'undisturbed' samp les. A misclassification matrix was used to show the disparity between description and measurement. Errors in the description of strength ma y have accounted for discrepancies of one class but not of two and thr ee classes. This suggests that the sampling process tended to result i n weakening probably due to stress relief and sample disturbance effec ts.