The effect of the stress path and the initial grain size distribution on grain crushing was investigated onudartificial material of a sand grain size. The thesis consists of two parts. In the first part isotropicudcompression test, oedometer test, conventional triaxial test (at constant cell pressure) and triaxialudcompresion test with constant mean effective stress are analysed. For the purpose of the researchuddescribed in this part of thesis crushed artificial material known under commercial name LightudExpanded Clay Aggregate was used. Based on findings gained from the analysis a model describingudgrain crushing and changing of internal friction angle was prepared. In second part of the researchuddifferent ways of crushing modelling were analysed. Two ways were then briefly tested. For theudapproach that showed to be better describing grain crushing a complete model was prepared togetherudwith all the measurements needed to track the sample behaviour during simulation. At the end theudmodel was tested. It turned out that the application of parallel bonds in modelling grain crushing isudunnecessary. The main reason for parallel bond application in the model was good description ofudtensile grain failure. Due to the high coordination numbers the tensile grain splitting is unlikely toudoccur. Instead, shear grain failure at contact is the most common grain failure. Therefore, contactudbonds, which are much more computationally efficient, should be used instead. The sampleudpreparation procedure with application of elementary particle expansion method turned out to beudunsuitable. Since for different grain size distributions with the same initial porosity, the stressesudinduced with this procedure can vary significantly. Compaction of the sample layer by layer wouldudmuch better serve this task.
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