Kunming Metro Line 4 realizes Kunming's first shield tunneling underneath the Metro Line

On October 28, the right-hand line of the Donghua-Dashuying section of Kunming Metro Line 4, built by the Urban Rail Branch of the Fourth Bureau of China Railway, smoothly penetrated Kunming's first shield tunneling machine into the subway line 3.
      It is understood that line 4 project Donghua Station - Dashuying station section of the right line is slanting down through line 3, the length of 38.37 meters. Shield tunneling under the subway line is the key and difficult point of the construction, for the construction, quality and safety, monitoring and other aspects of the work have very high requirements.
      The next line 3 is characterized by distance and difficulty. The minimum distance between the crossing section and the operation line is 2.43 meters, and the hydrogeological conditions are complex. The shield tunneling under the tunnel can easily cause disturbance to the stratum, which will affect the operation safety of Line 3. The subway operation requires high settlement of the track bed and strict settlement control during the construction process.
      In order to ensure the smooth underpass of the shield, the construction unit has taken four measures, formulated a targeted technical scheme, invited experts to demonstrate; set up a leadership system, side station system, improve the emergency management system, early inspection and preparation; at the same time, strengthen links with external units to ensure construction. Smooth development.
      Previously, affected by the Kunhe metre track suspension and upgrading, the station was suspended until December 31, 2017, the main project and section reinforcement was resumed. It is reported that in the station affected by metre track in line 4, this is the first to complete the construction of envelope structure, the first to realize the start of shield tunneling, and the first shield tunneling smoothly through the subway line.