Improved TBM side cutter life prediction method considering rock integrity and TBM tunnelling attitude

Cutter life is an important economical index for TBM excavation, and its prediction is widely concerned. In our past researches, a TBM cutter life prediction method is proposed. According to the data collected by the 6th section of the Qingdao metro project, it is found that our past method is suitable for predicting the normal cutter life, but the predicting effect of the side cutter life needs to be improved. The key of our past method is to calculate the consumption coefficient of the tunneling area, which means the consumption of cutter life by tunneling through unit length and is a function of uniaxial compressive strength (UCS) and Vicker's hardness number of rock (VHNR). In this paper, the consumption coefficient is modified to be more suitable for side cutters, by involving two new key influencing factors, joint frequency (Jf) and TBM tunnelling attitude (alpha), into the regression. The modified consumption rate is calculated according to 94 samples collected from test area I, with the total length of 895m. The proposed method is verified by 98 samples collected from another test area with more complexed and different test area, with the total length of 822 m. The prediction results of the proposed method have high consistence with the actual value. Compared with our past method, the side cutter life prediction accuracy of the proposed method is higher, which is only 22.4 %. The results proved the proposed method is effective for predicting the side cutter life.