Random Testing for Anchor Capacity in Tunnels

[VoyageofDiscovery]

If the application is within a highway tunnel, such as the the collapse in Boston, what is the accepted failure level within a group of mechanical anchors.

VOD

 

[Tramway]

Generally the number of pull tests that are conducted should be mapped in conjunction with the geologic cross section to determine if it's needed to address a specific area of "bad ground". Going back and retouque testing of any problem areas should be done to detect, map and consider any post excavation changes in Ft-Lb torque on bolts. Bad ground areas need to be measured for any movement before lining & concreting tunnel.