Evaluation of the Resilient Modulus of the Dunaújváros Loess Soil According to the MEPDG

Abstract

The resilient modulus (MR) of the earthworks is a basic input parameter of the new alternative design method of pavement structures. Its value depends on the stress state and the properties of the soil. In the literature several models are available that are based on directly measured results, thus they make possible to determine the value of the resilient modulus in case of different stress levels. Thanks to these models, the resilient modulus could be determined on stress levels that are not possible to make direct measurement on. It enables also to choose a correct MR value even if the expected stress state changes during the design procedure. The most widely applied model is the universal model recommended by the Mechanistic-Empirical Pavement Design Guide that can be fitted to a certain soil by regression coefficients. Several researches were conducted to determine these regression parameters to many types of soils, most of them produced the coefficients as simple numbers. However, some literature recreates the regression parameters as functions of basic soil properties, making a more complex attempt to fit the model to a given soil type. In this paper the parameters of the MEPDG model were examined and fitted to a typical soil type: the loess soil origins from Dunaújváros in Hungary. Equations were established to determine the regression coefficients as function of more simple parameters the determination of which requires simpler and less costly tests than that of the direct cyclic triaxial resilient modulus measurements.