5. Construction ventilation effect
On November 27, 2009, the ventilation effect test was carried out for each tunnel opening, and the ventilation effect of each working face was good. Taking the No. 10 inclined shaft as an example, the construction area used 4 working faces to construct at the same time, and the air quality met the sanitation and safety of the plateau alpine tunnel construction. Environmental control standards, the measured results are shown in Table 5.
Table 5 No. 10 inclined shaft ventilation effect monitoring data table
| Location | Ventilation method and status | Measuring point location | On-site work status | palm mileage | Ventilation distance and the length of the
tunnel ventilation duct from the face （m） |
Measurement item | ||
| O2 content(%) | CO content(ppm) | H2S content(ppm) | ||||||
| No. 10
Inclind shaft |
Clapboard ventilation,
fan power 2x55kW |
I line Xining direction face | mucking and removing, ventilated | DK307+384 | 1358/25 | 18.5 | 53 | 60 |
| I line Golmud direction face | Gunite, ventilated | DK309+798 | 1940/25 | 19.0 | 3 | 0 | ||
| Ⅱ line Xining direction face | Palm stops working, ventilated | DK307+350 | 1392/30 | 18.9 | 6 | 0 | ||
| Ⅱ line Golmud direction face | Palm stops working, ventilated | DK309+809 | 1942/30 | 19.1 | 3 | 0 | ||
6. Conclusion
6.1 The Guanjiao Tunnel is currently the longest mountain tunnel under construction in China. It faces major technical difficulties in construction ventilation at high altitudes, long distances, and multiple working faces. The ventilation standards implemented in various countries in the world are generally between 3 and 8m3/(kW·min). According to the actual situation in my country, the implementation sanitation standards for the construction of high-altitude Guanjiao tunnels are proposed.
6.2 According to the various construction organization forms implemented in the Guanjiao Tunnel, through systematic theoretical research and field tests, the staged construction ventilation and the mixed ventilation of the inclined shaft clapboard roadway are proposed, which successfully solves the construction ventilation problem. The long tunnel construction has accumulated successful experience.
6.3 The four working faces of Line 1 and Line II are used for the construction of the inclined shaft in the construction of the positive tunnel at the same time. The test results show that the ventilation effect of each working face is good, and the air quality meets the ventilation standards.
End
Post time: Jul-04-2022
