Tutorial 18 - 3D Tunnel Simulation using Core Replacement

In this tutorial, Phase2 is used to simulate the three-dimensional excavation of a tunnel. In three dimensions, the tunnel face provides support. As the tunnel face advances away from the area of interest, the support decreases until the stresses can be accurately modelled with a two-dimensional plane-strain approach. We will simulate this effect by gradually softening the material inside the tunnel and observing the change in tunnel wall deformation. Support is installed in the tunnel when an appropriate amount of deformation occurs.

3D Tunnel Simulation (click to view PDF file of tutorial)

Topics Covered in this Tutorial

3D tunnel simulation using core replacement

Alternate Method

An alternative approach to the material softening technique is demonstrated in the following tutorial, using a near-surface tunnel.

3D Tunnel Simulation for Near-Surface Tunnel

However, note that in this example, the core is softened using a series of single stage models. This does not simulate the stress path as accurately as a multi-stage model with core replacement using different materials. As an additional exercise, it is recommended to re-do this example as a multi-stage model, as described in the core replacement tutorial above.