top of page

Excavation and Trench Stability Assessment

Excavation failures are particularly dangerous because they may occur quickly, limiting the ability of workers to escape especially if the collapse is extensive.

 

The speed of an excavation collapse increases the risk associated with this type of work and the consequences are significant as the falling earth can bury or crush any person in its path. This can result in death by suffocation or internal crush injuries.

A person conducting a business or undertaking must manage risks associated with all kinds of excavations at the workplace, no matter how deep.

​

Specific duties apply in relation to the higher-risk excavations such as trenches, shafts and tunnels. However, these requirements do not apply to a mine, a bore to which a relevant water law applies or a trench used as a place of interment.

​

Any construction work (including any work connected with an ‘excavation’) that is carried out in or near:

​

  • a shaft or trench with an excavated depth of greater than 1.5 metres, or

  • a tunnel

​

Excavation work may also seriously affect the security or stability of any part of a structure at or adjacent to the location of the proposed excavation which can lead to structural failure or collapse. Excavation work must not commence until steps are taken to prevent the collapse or partial collapse of any potentially affected building or structure.

 

Any excavation that is below the level of the footing of any structure including retaining walls that could affect the stability of the structure must be assessed by a competent person and secured by a suitable ground support system which has been designed by a competent person. Suitable supports to brace the structure may also be required and should be identified by a competent person.

​

NSW WorkCover Excavation Work Code of Practice 2015 states that benching and battering of excavation walls can minimise the risk of soil or rock slipping onto the excavation. Control measures should be designed by a competent person (eg geotechnical engineer) and be relative to the soil type, the moisture content of the soil, the planned height of the excavated face and any surcharge loads acting on the excavated face and any surcharge loads acting on the excavated face.

​

At Greywacke, we offer various solutions to overcome potential impacts of excavations to adjacent structures and OHS hazards. We also advice on the suitability of earthwork methods, impact minimisation strategies and appropriate excavation methods.

​

​

bottom of page