Table 6 Principal stress sudden rotation angles at the monitoring point of the arch crown in elastic and elasto-plastic states.
Excavation steps | Angles between principal stresses and x, y,z axes in elastic stage | Angles between principal stresses and x, y,z axes in elasto-plastic stage | ||||
|---|---|---|---|---|---|---|
σ1 | σ2 | σ3 | σ1 | σ2 | σ3 | |
Step26 | 76°,59°,35° | 14°,82°,79° | 89°,32°,58° | 83°,6°,44° | 7°,85°,86° | 89°,43°,47° |
Step27 | 4°,88°, 86° | 86°,41°,50° | 89°,50°,41° | 3°,89°,88° | 88°,21°,69° | 88°,69°,21° |
Step > 30 | Stabilize | Stabilize | Stabilize | Stabilize | Stabilize | Stabilize |
