# Research on an Evaluation Method for the Adaptability of TBM Tunnelling
## 3 Selection of Evaluation Index and Establishment of Fuzzy Function  
### Selection of Evaluation Index  
The factors affecting open-TBM tunnelling include TBM tunnelling parameters, geological conditions, and adverse geology. After data analysis and summary, we found that there are 19 influencing indexes, including the following: 1. penetration rate, 2. thrust,  
Figure 2: The geological profile of the interval tunnel; (**a**) K112+000-K114+000, (**b**) K2+310-K4+310, (**c**) K18+500-K20+500.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Section**} & **Tunnel** & **Tunnel** & **Buried** & **Uniaxial Compressive** & **Rock Mass Integrity** \\  & **Length (m)** & **Diameter (m)** & **Depth (m)** & **Strength of Rock (MPa)** & **Coefficient** \\ \hline K112+000-K114+000 & 2000 & 7.8 & 15–92 & 92–96 & 0.78–0.84 \\ K2+310-K4+310 & 2000 & 7.0 & 95–119 & 65–71 & 0.52–0.58 \\ K18+500-K20+500 & 2000 & 5.5 & 193–239 & 67–73 & 0.40–0.44 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Interval tunnel parameter statistics.  
3. rotations per minute (RPM), 4. torque, 5. penetrations per revolution (Prev), 6. uniaxial compressive strength, 7. rock mass integrity coefficient, 8. crustal stress, 9. Cerchar abrasivity index (CAI), 10. number of rock mass joints, 11. fault fracture zone, 12. large deformations of the surrounding rock, 13. water inrush, 14. rock burst, 15. high geopentperature, 16. harmful gases, and 17. weak and uneven stratum. These 17 indexes can be divided into three categories, in which indexes 1-5 belong to tunnelling parameters, indexes 6-10 belong to geological conditions, and indexes 11-17 belong to adverse geology.  
In order to strengthen the operability of the method proposed in this paper and the weight of subsequent evaluation indexes, we use the expert scoring method to score and screen the 17 indexes.  
The nine-scale method is selected as the scoring method. The nine-scale method comes from the principle of psychology. It is possible for people to judge the relative difference between two objects through a sensory thinking comparison. At the same time, the psychological limit that can distinguish the difference is 7 \(\pm\) 2. Therefore, when using the nine-scale method, if the expert scores eight or nine, we will round off this index to improve the accuracy of the evaluation.  
The key to the expert scoring method is to select appropriate experts for the scoring and evaluation; therefore, these experts must have a solid professional foundation, rich on-site work experience, and a fair and rigorous scientific attitude. Based on the above requirements, four professors engaged in TBM and tunnel engineering research for many years and three project chief engineers with rich experience in TBM tunnel engineering were selected. Combined with the specific conditions of Xinjiang hydraulic engineering, they were asked to use the nine-scale method to score the 17 indexes proposed above to judge the influence of different indexes on the adaptability of TBM tunnelling.  
The scoring results of the 17 indexes in the three categories by seven experts are shown in Tables 4-6. Based on the scoring results, 11 indexes with the greatest influence on TBM tunnelling adaptability are selected, which are the following: 1. RPM, 2. torque, 3. thrust, 4. uniaxial compressive strength, 5. rock mass integrity coefficient, 6. crustal stress, 7. CAI, 8. fracture zone, 9. large deformations of the surrounding rock, 10. water inrush, and 11. rock burst. On this basis, the evaluation index system of the TBM tunnelling adaptability of Xinjiang hydraulic engineering is constructed, as shown in Figure 3.