Project Name：Dujiangyan–Siguniang Mountain Rail Transit DSZQ-4 Section

Project Unit：China Railway 18th Bureau Group Tunnel Engineering Co., Ltd

Geological Condition：The tunnel faces harsh geological conditions, with well-developed rock joints and fractures, multiple fault zones, and intrusions of smaller rock bodies such as diabase and amphibolite. The rock hardness ranges from 150 to 200 MPa, with alternating hard and soft layers forming a "toothed" geological structure. 

Project Description：The Dujiangyan–Siguniang Mountain Rail Transit DSZQ-4 Section Tunnel has a total length of 10.4 kilometers, with approximately 7,467 meters excavated by TBM. To address the complex geological conditions of the Zijing Tunnel, a customized 10.23-meter-diameter TBM named "Shutong" was developed, providing strong support for the rapid advancement of tunnel construction.

Cutter Solution：To cope with extremely hard rock, special high-strength cutter rings were designed using steel containing rare alloy elements to improve both hardness and toughness, allowing them to withstand immense rock-breaking impact forces without cracking. For strata with uneven hardness, the cutter layout and angles were optimized to enable different cutters to operate efficiently in rocks of varying hardness, reducing uneven wear and damage. This solution fits the complex and variable geological conditions, ensuring stable TBM tunneling.