On May 10, Qingdao Metro Line 5-2-8 Section of Chengtong Company under China Railway No.2 Engineering Group reported good news: the TBM on the left line of the section between Qingyi East Hospital Station and Shilaoren Bathing Beach Station has successfully launched. This is the second TBM launched by the project this year, marking that the project has officially entered the dual-line TBM tunneling stage.

It is reported that after launch, the TBM in the Qingshi section will enter a tectonic fracture zone, where the surrounding rock of the tunnel is broken and poorly stable, with risks such as large rock mass collapse, machine jamming and water inflow. In response, the project carried out advance planning, prepared a special construction scheme for ground grouting, organized experts to review the scheme, and strictly followed the scheme requirements by adopting ground retreating grouting measures to treat the tectonic fracture zone in advance, and verified the strength and impermeability of the reinforced body by coring verification. Test results show that the reinforcement effect is good and can effectively ensure the smooth passage of the TBM.

During construction, the project team focused on the main line of Qingdao Metro team building of "two entries, three rings, four controls and five guarantees", actively summarized the advanced experience of team building from sister units, and took team building as an important lever to promote TBM construction management. Since the launch of the first TBM on April 8, the party-member and management personnel assigned to teams (referred to as "two-entry personnel") have been highly integrated with the teams, fully playing the linking role of guidance, assistance and gap-filling in on-site construction and production as well as workers' food, clothing, housing and transportation. In particular, to ensure the quality of the formed tunnel, team members, driven by the "two-entry personnel", successively put forward "small suggestions" such as "using segment tie devices to ensure segments do not deform" and "adopting dual-liquid grout temporary consolidation measures", which were adopted, effectively reducing the segment misalignment rate and effectively improving the team's construction management level.