1. Guanjiao Tunnel Project Overview
Guanjiao Tunnel is located in Tianjun County, Qinghai Province. It is a control project of the xining - Golmud extension line of Qinghai-Tibet Railway. The tunnel is 32.6km long (the inlet elevation is 3380m, and the export elevation is 3324m), and it is two parallel straight tunnels with the line spacing of 40m. The annual average temperature in the region is -0.5℃, the extreme minimum temperature is -35.8℃, the average temperature of the coldest month is -13.4℃, the maximum snow thickness is 21cm, and the maximum freezing depth is 299cm. The tunnel area is alpine and hypoxic, the atmospheric pressure is only 60%-70% of the standard atmospheric pressure, the oxygen content of the air is reduced by about 40%, and the efficiency of machinery and personnel is greatly reduced. The tunnel is constructed by drilling and blasting method, and 10 trackless transport inclined shafts are used to assist the construction of the main tunnel, that is, 3 inclined shafts are set in the tunnel of line I and 7 inclined shafts are set in the tunnel of line II.
According to the construction organization design, the task arrangement of tunnel entrance and exit and inclined shaft working area is shown in Table 1. Considering the changes and adjustments in actual construction, each inclined shaft working area has the requirements of simultaneous construction of the inlet and outlet of line I and line II. The maximum single-head ventilation length should be 5000m, and the altitude of the working area should be about 3600m.
To be continued…
Post time: Jun-08-2022
