Abstract: The wastewater pump room constructed by conventional mining method has disadvantages of long construction period and high risk, and the wastewater pump room in connection gallery constructed by mechanized method is limited by small operation space and high risk of secondary segment dismantling. Accordingly, mechanized construction method is proposed for wastewater pump room in shield tunnel, and two essential techniques of upper joint and bottom sealing are clarified. Then, numerical simulation method is conducted to analyze the influence of ground water pressure on mechanical properties of sealing concrete. The results of the techniques have been applied in wastewater pumping station in a shield tunnel of Wangjingxi stationYongshiying station tunnel section of Beijing metro line 17. The resalts show that: (1) Under the condition that the safety factor larger than 1.4, the bottom sealing water pressure of 1.0m thick C30 sealing concrete can be used for the formation condition that does not exceed 0.3 MPa water pressure. (2) The corner of the connection between the bottom sealing concrete and the outer shield is weak, and its failure mode shows a gable slope shape distribution. (3) The mechanized construction of wastewater pump room with large volume in shield tunnel can effectively control the construction quality, reduce the stop time of submerged pump, the maintaining time and cost, and influence on line operation.

Key words: metro engineering, shield tunnel, mechanized construction technology, wastewater pump room, pump room sealing