Application of an interval wear analysis method to cutting tools used in tunneling shields in soft ground

The replacement of cutting tools is important when shield tunneling in abrasive soils. The task is performed based on an assessment of the degree of cutting tool wear. The wear of cutting tools is influenced by many factors, such as the soil abrasiveness, shield machine operational parameters, and tool sliding distance. The representation of the uncertainty in these factors is the primary problem in the evaluation of tool wear. Instead of real variables, interval variables are employed to represent the uncertainty in the influencing factors, and the interval of the tool wear amount is attained based on interval arithmetic operations. With the calculated interval for the amount of tool wear and the dimensionless indices η and ξ, the feasibility of completing shield tunnel construction with tool wear within a predefined tolerance is quantitatively evaluated. Measures and countermeasures can be implemented based on the results of the evaluation. A five-step process for conducting an evaluation is described and explained using an example application. The suggested methodology can help realize active tool replacement and obtain cost-effective and less-disruptive solutions for shield cutting tool wear in tunnel construction.