RISK – Ground Collapse
The permit conditions will be discussed at every pre-start meeting with ground support requirements as a condition of entry clearly stipulated.
A Permit to Tunnel must include and/or consider:
- Duration the permit is valid for
- Excavation and ground support type / requirements
- Maximum advance length
- Activities covered under the permit
- Survey & monitoring requirements
- Definition of supported ground required prior to personnel entry
- Testing and quality requirements
Once the Permit to Tunnel (PTT) and subsequent permit requirements have been identified and drafted, the permit will be reviewed and signed off by the Geotechnical Engineer, Construction / Tunnel Manager, Design Representative and Superintendents / Foremen.
Once all the above have approved and signed, the permit is ready for use and considered fit for purpose. The Shift Supervisors/Managers will then be briefed on the permit conditions, which they will then communicate at the daily pre-start.
The Permit to Tunnel is only valid for a defined period. For underground excavations, it is recommended that this period is 24 hours.
Related GMRs
2.1 Assess excavation design requirements and implement appropriate protective systems
Related Procedures / Forms
Permit to Tunnel - This must be jointly developed with tunnel designers and tunnelling team as requirements vary