Equipment:

Two HK slurry TBMs with a diameter of 15.76 meters are used.

Project Information:

The Sanyang Road Cross-river Tunnel is the first super-large-diameter highway-rail cross-river tunnel in the middle and upper reaches of the Yangtze River, with a total length of 2,590 meters.

Difficulty:

The difficulty of the construction is that the upper part of the stratum in the center of the river has a high content of quartz, and the lower part of the section has a high content of high-strength gravel of more than 20mm in the weakly cemented conglomerate. The skeleton is composed of quartzite and limestone, and the cutters wear rate is fast.

The original ripper has poor tearing ability on the tunnel face, which causes the torque of the cutterhead to increase, which is not suitable for this formation.

Solution and improvement measures:

In order to meet the needs of the cutter to adapt to the changing stratum at any time, we made a series of improvements to the soft soil cutters, and only the normal pressure can replace the pioneer cutter to modify more than 10 types.

"Pagoda cutter" is a special forward cutter designed for this project. The carbide layout of the cutter is a layered structure. The upper carbide is 70mm wide and the lower carbide is 140mm wide. It can completely cover and even coincide the excavation of the face. The addition of the lower layer carbide plays a role of diversion, reduces the secondary wear of the cutter, and doubles the life of the cutter. The successful design of the cutter played a vital role in the smooth penetration of the tunnel.