Observations of tool wear and excavation performance in urban tunnels

One of the most important predictions in a mechanized excavation project is the performance of the excavation Rostami et al., (1994), Bilgin & Balci, (2005). To obtain an efficient ground excavation in mechanized excavation it is important to achieve an efficient interact between cutting tools and ground. This is clearly fundamental to be able to gauge and evaluate this efficiency and the best paramenter to do it with is specific energy Gertsch et al., (2007), Frenzel et al., (2008). But during the excavation process the cutting tools are themselves worn Beste & Jacobson, (2008), Thuro et al., (2006) and the larger the tool wear, the lower the cutting efficiency. It is this wearing effect of the excavation process that abrasivity measures aim to quantify, Johnson & Fowel, (1986), Nilsen et al., (2006). A good parameter to measure the efficient interaction between soil/rock and tool should be one that would let us know from an integral point of view how appropriate the machine design and its tools are for the project geology. Specific Energy (SE) is proposed as this parameter.