Document ID: chunk:federal_register_of_legislation:F2016L00416:reg:4:p9
Version: federal_register_of_legislation:F2016L00416
Segment Type: reg
Provision Reference: reg 4 (pt 9/21)
Character Range: 53574–56556

trench and there is a risk of engulfment, these control measures should be implemented regardless of the depth of the trench.

A report from a geotechnical engineer may be required to provide information on the stability and safety of a trench excavation. The report should include details of the soil conditions, any shoring or trench support requirements, dewatering requirements and any longer term effects on stability and safety of the excavation. A competent person (for example an engineer) should design any support systems or be involved in the selection of other ground collapse control measures, such as trench shields.

Shoring, benching and/or battering may not be required if written advice is received from a geotechnical engineer that all sides of the trench are safe from collapse. Any advice should
state the period of time to which it applies and may be subject to a condition that specified natural occurrences may create a risk of collapse.

Preparation and excavation
Bulldozers, scrapers, excavators and other types of earthmoving equipment are commonly
used for either preparing work areas prior to trenching or for the trenching work itself.

For some trench excavations manual work, such as trimming by hand, will be required. Trimming can often be accomplished from outside the trench by shovelling or pushing the material with
a long handled tool or shovel to the bottom of the excavation where it can be picked up by
the excavation plant. Risks associated with falls and working with powered mobile plant must
be controlled.

    5.2              Tunnelling

The nature of tunnelling work is complex and highly specialised, requiring high levels of engineering expertise during the planning, investigation, design and construction stages.
Design
Safe tunnel construction depends on adequate pre-construction engineering investigation of
the ground and site and accurate interpretation of the information obtained. Designers should:
    * obtain or be provided with all available relevant information
    * be advised of any gaps in the information for planning and construction
    * undertake or be involved in data acquisition for the site investigation program, and
    * have on-site involvement during the engineering investigation.
The information obtained from the engineering investigation and the anticipated excavation methods should be considered in preparing a tunnel design. The design should include:
    * details on the tunnel dimensions and allowable excavation tolerances
    * temporary and final support and lining requirements for each location within the tunnel
    * details of expected tunnel drive lengths and location of shafts, and
    * any other requirements for the finished tunnel.
The design should also include information on the excavation methods and ground conditions considered in the design. This will allow the design to be reviewed if another excavation method is chosen or the ground conditions differ from that