Abstract:

Chongwenmen station on line 5 of Beijing Metro crosses underneath line 2 of Beijing Metro, with the clearance between the crown of Chongwenmen station tunnel to the structural bottom slab of the existing Metro line being only 1.98 m. The construction method for Chongwenmen station tunnel is optimized on basis of engineering analogy and insitu tests on roof pipes. Central drift method is applied to turn the large span of the station tunnel into small spans and heading method is applied for the excavation of the central drift so as to minimize the settlement. The rule of the settlement of the existing Metro line is analyzed by numerical analysis method so as to understand the key points of the construction. Assistant construction measures, such as advance grouting, compensation raising grouting and advance reinforcement by  600 interlocking roof pipes, are recommended on basis of the monitoring results and numerical simulation results. In the end, the settlement of the existing Metro line is effectively controlled, with the final settlement value being less than 20 mm.

Key words:  Metro station, construction, pipe roof, existing Metro line, settlement control