Over the years, many researchers have studied the complex behaviour of granular materials, using laboratory and in situ testing techniques. An extensive literature review was carried out by Lekarp et al. (2000) to collect findings from previous research and summarize in two companion papers the state of knowledge on resilient and plastic properties of granular materials. In this work the authors point out that these properties are affected by numerous factors such as stress, density, grading, moisture content, stress history, particle shape and load frequency, nonetheless the effect of stress parameters is certainly dominant.
If granular materials are simulated by means of Layered Elastic algorithms or using the Method of Equivalent Thickness, this stress dependency is usually dealt with through iterative processes (Figure 1):
 |
Figure 1: Iterative determination of resilient modulus
The complexity of the problem meant that a large number of models can be found in the literature. An interesting review of available models for the prediction of permanent deformations in UGMs has also been conducted as part of the SAMARIS project by Hornych et al. in 2004.
Hereafter we present a selection of the main approaches to resilient and permanent behaviour of UGMs that might be implemented in the WLPPS.
0 comments:
Post a Comment