Abstract:

The technology of roof ripping between large crosssectional inclined shaft (with the crosssectional area reaching 84.315m2) and main tunnel is presented, with the roof ripping construction between No. 1 inclined shaft and main tunnel of Baojiashan tunnel as an example. The construction scheme of advance reinforcement, sequential excavation, strengthened primary reinforcement, supporting immediately after excavation, timely ring closing and strengthened monitoring is established on basis of fully understanding of the geological conditions. The construction method for the connection section is focused. The construction experience is summarized. The paper can be served as reference for similar projects in the future.

Key words: tunnel, large cross section, inclined shaft, roof ripping