Table 5 The principal stress deflection angle of the monitoring point at the arch waist under elastic and elastoplastic conditions.
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 | |
Step 30 | 88°,89°,0° | 68°,15°,6° | 11°,87.5,83° | 87°,89.6°,2° | 81°,8.3°,8° | 11°,78°,86° |
Step > 30 | Stabilize | Stabilize | Stabilize | Stabilize | Stabilize | Stabilize |
