Recently, the right-line shield of the section from Chuanjin Road Station to Kunming North Railway Station (Chuan-Kun Section for short) on Kunming Metro Line 5 was successfully received.
The right line of the Chuan-Kun Section is 414.788 meters long in total, with 346 rings. The tunnel crown burial depth is about 15.6 to 19.3 meters, and the maximum gradient of the section is 22.31‰. The spacing between the left and right lines of the section gradually transitions from 14 meters when departing Chuanjin Road Station to complete vertical overlap at Kunming North Station; that is, the alignment transitions from horizontal parallel running to vertical overlap.
To ensure smooth and controllable shield construction, the project department communicated with the general contractor, owner, survey, power supply, water supply and other units many times, completed detailed geological exploration and underground pipeline network investigation, and formulated a practical shield construction plan.
At the same time, in view of the characteristics of the water-rich gravel stratum, such as strong permeability and high water pressure that easily lead to water and sand inrush, shield seal failure, and leakage, during shield tunneling, shield personnel carried out simultaneous grouting and secondary grouting, and equipped six dewatering wells for timely dewatering.
“During the receiving stage, we adopted the steel sleeve receiving method. This method can effectively avoid risks such as water and sand inrush during shield receiving, and can carry out portal sealing and grouting backfill under closed conditions, thereby ensuring safe shield receiving,” introduced Pang Zifeng, work area manager of the shield team.
At present, shield machine dismantling operations are in full swing.