Qinling Water Diversion Tunnel

1. Engineering Significance

The Hanjiang-to-Weihe River Water Diversion Project addresses water scarcity in Shaanxi by transferring water from the Hanjiang to the Weihe River, supporting multiple regions and restoring local ecology. The Qinling Water Diversion Tunnel, the first large-scale tunnel across the Qinling Mountains, is a key part of this critical project.

2. Key Technical Challenges

The northern section of the Qinling Tunnel faces complex geology, high in-situ stress, and frequent rock bursts (8,012 recorded in two years), with traditional support methods proving ineffective. In response, Academician He Manchao’s team proposed the Excavation Compensation Theory, which explains how excavation disrupts rock stress, causing instability and bursts. To address this, they developed a high-stress compensation system using second-generation micro NPR bolts, axial flexible nets, and circumferential W-shaped steel strips. Field data from the Qinling Tunnel showed that this system effectively controlled rock bursts, reduced microseismic activity, improved rock integrity, and enhanced tunnel stability in high-stress, fractured sections.

Figure 1. Schematic diagram of the excavation compensation theory and 3D NPR support system