This lesson illustrates the use of PLAXIS for the analysis of the construction of a NATM tunnel. The NATM is a technique in which ground exposed by excavation is stabilized with shotcrete to form a temporary lining. Rapid and consistent support of freshly excavated ground, easier construction of complex intersections and lower capital cost of major equipment are some of the advantages of NATM. Some of the limitations of this method are that it is slow compared to shield tunnelling in uniform soils, dealing with water ingress can be difficult, and it demands skilled manpower.
This exercise requires the activation of the Geotechnical SELECT entitlements [GSE] in order to be able to use the tunnel designer.
The attached *.p2dxlog file contains all the commands to generate the model. With a Bentley Geotechnical SELECT Entitlement [GSE] license, you can use the commands runner to open the *.p2dxlog file and to execute all commands in one go, see also this instruction.
PLAXIS 2D Tutorial 04: Settlements due to tunnel construction [Tutorials]
PLAXIS 2D Tutorial 06: Dry excavation using a tie back wall [Tutorials]