Abstract:

 In order to improve the construction efficiency of the earth pressure balance(EPB) shield tunnel transportation system, a case study is conducted on the phase 1 project of Beijing metro new airport line. Furthermore, two adjacent shield sections with different muck transportation modes are selected to establish a construction material and muck transportation model of the EPB shield. In addition, two transport modes, the rail transport system and rail transport + belt conveyor (including horizontal continuous belt conveyor + vertical belt conveyor) combined system, are compared and analyzed. The results reveal the following: (1) The rail transport system is preferred when the transport distance is less than 600 m. (2) When the transportation distance is between 600 m and 1 700 m, the construction efficiency of the two methods is essentially identical. (3) When the transportation distance is greater than 1 700 m, the combined transportation system should be preferred. Compared with the combined transportation system, the onsite construction continuity of the rail transportation system is poor, the measured tunneling cycle time is larger than the theoretical prediction, and the time difference increases gradually with the transportation distance. Compared with the theoretical prediction, the measured driving cycle time difference of the combined transportation system is smaller, and it is easier to reach the ideal construction expectation in the actual construction process.