SIMILARITIES BETWEEN THE MECHANICAL BEHAVIOUR OF SUGAR CANE BAGASSE AND PEAT SOIL

PREVIOUS work has shown that the general mechanical behaviour of prepared cane and bagasse is basically identical to that of soil (sand, clay). The compression, shear and volume behaviour of bagasse follows the critical state behaviour outlined in soil textbooks. This soil behaviour has been implemented in critical state material models. Some of those models have been used in milling research over the past 10 years for modelling milling units. It is of little surprise that some limitations have been identified in the ability of the models to reproduce bagasse behaviour, since that was never the intention of the model developers. The soil type that most resembles bagasse is peat; in particular, Radforth Peat, which is highly fibrous and has little mineral content, seems to display identical mechanical behaviour to prepared cane and bagasse. The difficulties in measuring bagasse and peat behaviour are strikingly similar. The research carried out on bagasse is quite limited. In contrast, far more work has been carried out on the measurement and modelling of the mechanical behaviour of peat. Some researchers in the peat field have made notable advances, and as a result, high quality data for peat properties have been obtained. This paper describes the similarities between peat and bagasse. It describes the high quality measurements on peat in the context of modelling bagasse behaviour, and their relationship to features in material models that are more suitable for bagasse. High quality data from the peat literature is presented that provides information on the values of material parameters that are likely to be adequate for prepared cane and bagasse, and a peat material model from the same source is introduced that is likely to be a further improvement on the material models currently being used in mill modelling. The measurement equipment and techniques used for measuring peat behaviour are readily applicable to characterise bagasse behaviour.