An Index for Estimating the Stability of the Layered Rock Masses under Excavation Disturbance

Figure 10

Isolines for the point safety factor and collapse of the rock mass around the section at stake K 0 + 310 after the excavation of the first layer of the #4 diversion tunnel: (a) isolines for the point safety factor and (b) collapse of the left spandrel.

(a)

(b)