The Use of Databases to Analyze Model Uncertainties of Geotechnical Design Procedures

The deviation of the predicted behavior of a geotechnical structure for a given design to its real behavior is commonly addressed by the model uncertainty of the applied design method. The model factor approach is the easiest way to express this uncertainty. Herewith, the model factor is defined as the ratio of the design quantity measured in a load test to its predicted value using the design method in question. Databases of well-documented field and laboratory tests are a good tool to quantify model factors. However, the number of load tests, the quality and quantity of information available for each test in the database determine significantly the model factor evaluation. The conditions at the test site such as the scale and geometry of the model or prototype, the soil characteristics, the test performance and the interpretation of the test results are identified to be of special importance for the quality of the database.