SUBGRADE MODULUS BASED ON THE BACKCALCULATION OF 2,220 DEFLECTION BASINS

Two models for estimating the SgMr (subgrade resilient modulus) as function of the SgCBR (subgrade CBR - California Bearing Ratio) were developed based on the backcalculation of 2,220 deflection basins. The results obtained from one of them, a long-log model, showed an excellent agreement when compared to the results found for the Transportation Road Research Laboratory (TRRL) model. Besides the fact that the equations developed in this research were generated with basis on true field data, one of their main advantages is that they are valid for SgCBR varying from 4 to 48, a common situation in subgrades of tropical soils. Another very important conclusion of this research is that the SgMr is not only a function of the SgCBR multiplied by a unique constant, as it is suggested by some models in the literature.