The Influence Mechanism of In Situ Stress State on the Stability of Deep-Buried-Curved Tunnel in Qinghai-Tibet Plateau and Its Adjacent Region

Table 3

The predictive equations and their adjusted R² values at key positions.

Position	Predictive equation	Adjusted R^2 (%)
Roof		99.97
Floor		99.98
Spandrel		99.97
Corner		99.97
Sidewall		99.99

The unit of is MPa; the unit of φ is rad.