Preliminary evidences on the influence of grains micro-structural features on the TBM tools wear

The wear of the excavation tools during the mechanized tunnelling in coarse grained soils is an extremely widespread phenomenon that should be taken into account to properly develop an excavation project. In fact, the excessive tools wear reduces the penetration speed, increases the energy consumption and requires stops necessary to replace the worn tools. Thus, to optimize the process, the tools consumption rate should be necessarily predicted in advance. Different works have focused the attention on the relationship between the tools wear and the quartz content of the soil to be excavated. In this research, a step forward is made focusing the attention on the role played by the morphology of the grains in the wearing process. The paper includes some experimental results of abrasion tests carried out on different sand samples. The results gathered lead to evaluate the influence of grain morphology of coarse soils on the wear of TBM tools. The experimental data reported are part of a wide research project aiming to link the mechanical behaviour of coarse soils with the grain morphology in different engineering applications.