Recently, the first earth pressure/TBM dual-mode shield machine for the entire Jinan Rail Transit Line 7 Phase I project successfully launched on the right line of the section from the Meteorological Bureau Station to the Olympic Sports East Road Station (both are project names, the same below), and construction on the section has entered an efficient shield tunneling stage.

"Taishan Hao", which is undertaking the shield tunneling task for the section from the Meteorological Bureau Station to the Olympic Sports East Road Station, is a dual-mode shield machine combining TBM and earth pressure tunneling modes, solving the technical difficulties of low tunneling efficiency of single-mode shield machines in extremely hard rock strata and the inability of TBMs to tunnel in composite strata. "Taishan Hao" has an overall length of 94 meters, a maximum thrust of 44,590 kN, and a maximum tunneling speed of up to 80 millimeters per minute. It launched from the west end of the Meteorological Bureau Station and will tunnel westward along Luyou Road to be received at the Olympic Sports East Road Station. The right line has a total length of 1.76 kilometers and will pass through rock and soil strata including moderately weathered limestone and locally diorite. The geology is variable, soft and hard uneven, and the rock strength is high. The maximum burial depth reaches 128.6 meters, and the rock strength is as high as 166 MPa, with the range exceeding 100 MPa approaching 300 meters, making the construction conditions exceptionally complex.

In view of the special working conditions of the section from the Meteorological Bureau Station to the Olympic Sports East Road Station, "Taishan Hao" adopted special designs at the initial design stage for high-strength hard rock, such as increasing the strength of the cutterhead, selecting wear-resistant screw conveyor barrel sections, and keeping standby shield tail grease pumps. It is equipped with a synchronous dual-liquid grouting and real-time backfill grouting monitoring system. The shield tail grease pumps use a one-duty-one-standby configuration. The cutterhead adopts eight foam channels, enhancing its ability to prevent mud cake formation. It pioneered the use of reinforced wear resistance and quick disassembly and assembly designs for the screw conveyor barrel sections. In particular, the main drive uses 7 sets of 200 kW motors, with a total power of up to 1,400 kW, making it the highest-power shield machine of the same diameter in China, improving construction efficiency and tunneling speed and ushering in the 2.0 era of Jinan-built dual-mode shield machines.

To ensure the smooth launch of the section shield, the project adhered to the concept of strengthening the "industrial chain" through the "Party building chain" and repeatedly invited experts from upstream and downstream industry chains to conduct feasibility demonstrations. By reasonably selecting the cutterhead opening ratio and cutter configuration scheme, it effectively improved the slag intake rate of the earth chamber, providing favorable conditions for efficient and stable shield tunneling. Before the shield launch, the project organized on-site technical, safety, and maintenance personnel to conduct technical and safety briefings on end dewatering, shield tunneling, synchronous grouting, segment assembly, and crossing buildings, structures, and pipelines, refining the division of responsibilities and laying a solid foundation for a smooth launch.