EQUIVALENT LINEAR ELASTIC MODULUS OF GRANULAR LAYER FOR LOW VOLUME ROADS

摘要

About 80 percent of the total road network in India comes under rural roads, which usually carry low volume of traffic and hence treated as low volume roads. Mostly these roads are constructed as granular pavements with or without thin bituminous surfacing. Therefore, properties of the granular layer have a significant role to play on the performance of these pavements as the thin surfacing layer is considered to be a non structural layer. Granular materials exhibit stress hardening characteristics especially in pavements with thin bituminous surfacing. The material property of the granular layer should be suitably modeled for reasonable estimation of the mechanistic pavement responses of a flexible pavement structure. Finite element codes are being effectively used for modelling the nonlinear material property of unbound materials. A three dimensional finite element model has been developed using ANSYS (2002) considering the stress dependent modulus of the granular layer. An empirical relationship has been developed in this study for selection of equivalent linear elastic modulus of" granular layer that will yield similar mechanistic responses as would be obtained considering nonlinear elastic granular layer. This will help the field engineers to use the values in any linear elastic pavement analysis programme to calculate the pavement responses without going for the nonlinear analysis, which is considered to be more complex in nature than linear analysis.