Influence of the slurry-stabilized tunnel face on shield TBM tool wear regarding the soil mechanical changes - Experimental evidence of changes in the tribological system

The wear of slurry shield TBM excavation tools is a challenging topic that has been discussed over many years, Due to the complexity of the tribological system that defines the tool wear, no sufficient approach to determine the wear in a specific tunneling project has been developed up to now. The elementary step to display the application-oriented tribological system is one of the main issues regarding laboratory scale test methods. Therefore, the RUB Tunneling Device has been developed at the Ruhr-University Bochum (Germany). With this apparatus, several influencing factors regarding the tribological system of a TBM-tool can be analyzed. A unique feature of the device is the experimental simulation of a slurry shield excavation, including a realistic tunnel face support. This paper focuses on the experimental simulation of slurry shield excavation and the influence of face support on tool wear. Changes in the soil mechanical properties due to slurry penetration at the tunnel face are regarded and correlated with the tribological system of a slurry shield excavation. It is proven that the tribological system, and thus the tool wear, changes significantly due to slurry injection.