Part 2: Evaluation of Subgrade Resilient Modulus: Resilient Modulus Estimation System for Fine-Grained Soils

Abstract

A software tool was developed to estimate the resilient modulus of fine-grained subgrade soils. The subgrade resilient modulus is a key factor for use in mechanistic-empirical pavement design methods. However, for routine design use, the test method is too expensive and difficult to perform. Resilient modulus estimation software was developed with expert system approaches. Information entered by the user is first examined for reasonableness and accuracy. Then, data searching processes are initiated, and more than 30 estimation models can be invoked, depending on the availability of input data. All results were evaluated on the basis of certainty rules, such as how well data meet limitations existing during the model's original development environment. The user is given four alternate methods on which to base the choice of a resilient modulus that is most appropriate for the site: one based on certainty rules and three based on statistical methods.