Optimum design of star layout for TBM cutting tool using gray wolves meta-heuristic optimization algorithm

 The cutting tool layout in the TBM cutter head is considered one of the most effective factors in improving the efficiency of boring operations, the TBM service life, the proper performance of the cutting tool, and reducing drilling costs.

In the design process of the TBM cutting tool layout, we faced a multi-objective optimization problem with nonlinear constraints, which caused computational complexity. In the present research, in order to evaluate the impact of cutting tool star layout on TBM performance, a numerical model has been developed using meta-heuristic GWO to design a star layout. Also, two types of star layouts (1: 8-pointed star, 2: 12-pointed star) were designed using the presented model, and the TBM performance was evaluated.

In order to evaluate the performance of the developed design model, the layout design process of the cutting tool in the cutter head of an operational TBM sample was evaluated. Based on the results, it is determined that based on the optimal 8-pointed star layout of the cutting tool, the lateral force Fs has decreased by 78.88% compared to the original layout of the cutting tool, and the eccentricity torque has decreased by 15.03%. Also, by evaluating the performance results of the TBM with optimal 12-pointed star layout, it was determined that the total lateral force Fs decreased by 87.89% based on the optimal 12-pointed star cutting tool layout compared to the original cutting tool layout and the eccentricity torque is reduced by 23.68%. From the comparison of the performance results of the TBM with an 8-pointed star layout and a 12-pointed star layout, it was found that the TBM with a 12-pointed star layout showed better performance. Based on the results, it is clear that the optimal star layout of the cutting tool in the TBM cutter head has improved the TBM performance from the point of view of drilling engineering (increasing efficiency and drilling progress). The most important result of this research included providing an efficient numerical model for designing the optimal star layout of the TBM cutting tool based on the grey wolf optimization algorithm. The presented model can be implemented under different operating conditions and for different types of TBMs.