# Key Technology of TBM Excavation in Soft and Broken Surrounding Rock
## Appendix C Verification of matching relationship between blade spacing and vertical force
### Grouting Equipment  
(1) Selection of grouting pipe  
The chemical grouting is used to consolidate the loose stratum or collapse. The grouting pipes used are different according to the consolidation positions; one is in front of the consolidation cutter head, and the other is at the top of the consolidation cutter head and the shield.  
The reinforcement of the broken surrounding rock in front of the cutter head is mainly to reinforce the loose surrounding rock by setting a grouting pipe in front of the face and around the cutter head through the cutter head, slag scraping port, and observation hole. Considering the particularity of TBM equipment, it is required that the grouting pipe in front of the cutter head can not only pre-anchor the face, but also cut easily during cutter head excavation. Therefore, cast iron pipes cannot be installed in front of the cutter head; otherwise, the cutter head will be easily damaged in the process of tunneling. In addition, given the low drilling rate of broken strata, it is appropriate to select a self-propelled hollow-glass fiber anchor; the specific self-propelled hollow-glass fiber anchor is shown in Figure 16. The reinforcement range shall be no less than 4.0 m in front of the cutter head and no less than 2.0 m in the radial direction of the side, as shown in Figure 17.  
Due to the narrow working space inside the cutter head, the length of a single section of glass fiber pipe should not be too long. The length of a single pipe is set to 1 m, and it is connected and extended with a sleeve. Use a handheld pneumatic drill or modified-air leg pneumatic drill (air leg length 1-1.5 m) to drill the glass fiber pipe into the loose body.  
As there is a large amount of slag on the cutter head and shield, the grouting conduit needs to have a certain rigidity to pass through the loose body for grouting. Therefore, the steel grouting pipe is selected as the grouting tool above the cutter head and shield. The grouting pipe is installed by \(\oslash\)42 grouting pipe (as shown in Figure 18). Since the front of the shield is loose and cannot be drilled, the T-28 drill is used to jack the small pipe with a sharp cone at the front end. When the pipe is difficult to jack, the glass fiber pipe can be used as the grouting pipe.  
Figure 16: Self-feeding fiber grouting pipe and connecting sleeve.  
Figure 17: Layout of chemical grouting pipe in front of cutter head.  
(2) Selection of grouting pump  
Chemical slurry does not need special metering slurry storage equipment, and its packaging barrel can be used as slurry storage feed and a metering barrel. The grouting pump is a 3 ZBQS-12/20 pneumatic grouting pump. The inlet pressure of this type of pump is 0.4-0.63 MPa, and the pressure is 3 m\({}^{3}\)/min, and an air compressor can be used. Automatically realize 1:1 volume feeding, mixing, and output, and the grouting pressure is 1-3 MPa. The grouting equipment is shown in Figure 19.  
(3) Chemical grouting effect  
The chemical grouting effect of weak and broken strata in Gaoligong Mountain is remarkable and plays a great role in the safe passage of TBM through unfavorable geology. The effect of the shield exposed by excavation after reinforcement is shown in Figure 20, which can effectively improve the stability of the surrounding rock.