Recently, at the 2,070 meter elevation platform of the Kunming Changshui International Airport expansion project, reporters observed that at the connection area between the main access roads and terminal area roads (west side) project and the T2 terminal, the cross section of the metro construction was clearly visible. Reinforcement splicing was underway for the pile foundations and pile caps of the main access road, and two spans of viaduct deck were being erected at the starting point of the road bridge.

“The total length of the project is nearly 10 kilometers, including viaducts and ground roads,” said Li Yanchen, project construction manager and staff member of MCC5, to reporters. As a key supporting project for the T2 terminal, this project mainly constructs the port front expressway, ground ramp bridges, and a multi level viaduct system connecting the domestic departure level and the international departure level.

At the construction site, reporters saw a pier column standing 18 meters tall on the platform. Li Yanchen told reporters: “This is pier column Q2 for the approach viaduct to the international departure level; its final height above ground will reach over 40 meters. The pile foundation below extends about 70 meters underground. Among the completed piles, the three longest have boreholes 93 meters deep.” Since the project is located in a karst development area and a high backfill zone, pile foundation construction is difficult. To ensure borehole quality, the construction team adopted a full casing follow through technique, where the casing is pressed in simultaneously with the rotary drilling rig, effectively preventing hole collapse.

It is understood that the biggest technical challenge of this project is the three dimensional intersecting construction with the metro project. Near the 2,070 meter platform and the GTC (comprehensive transportation center) under construction, the future Metro Line 6 will pass between the viaduct pier columns. “The metro will pass between four pier columns, from P1 to P4, with a minimum clearance of only a few centimeters,” Li Yanchen said, pointing to the construction area. “We need to repeatedly hand over the working faces with the metro contractor and enter the site separately. Currently, they have handed over the working face to us, and we are constructing. We expect to hand over four to five more times each way; the construction sequence is extremely complex.” In addition, the project also faces the challenge of multi level viaduct construction. “In the vertical area between the international departure level and the domestic departure level, the viaduct has three levels in total, each serving different functions,” Li said.

At the precast beam yard producing the viaduct beams, workers were welding rebar cages and pouring beam bodies. Liu Junyu, the on site manager, told reporters: “What you see now is the beam casting area. After the beams are made here, they are moved to the beam storage area by gantry crane, then lifted onto trailers and transported to the site for erection.” The precast yard is divided into a beam casting area, a beam storage area, and a rebar processing area, equipped with six gantry cranes. The largest has a lifting capacity of 98 tons, used for moving beam bodies; two 10 ton gantry cranes are used for moving rebar cages and internal beam molds. “For the west side project, three viaducts require concrete box girders, totaling 81 pieces. The other bridges will use steel box girders,” Liu said.

“Up to now, over 350 of the 678 pile foundations have been completed, with a completion rate exceeding 50%. Pier columns 0 to 6 have been completed, and the two spans of viaduct deck are about to be fully erected,” said Jiang Honghe, the project technical director. There are over 380 construction and management personnel on site.

According to the milestone schedule, it is planned that by the end of this year, the first viaduct leading to the parking building on the GTC side will be completed. By May 2027, the beam erection for the domestic and international departure levels will be finished, which will then provide an important transportation corridor for the construction of the T2 terminal.