Trench Shoring & Excavation Support SWMS
Trench shoring and excavation support — hydraulic shoring box installation, drag box use, soldier piles and lagging, engineered shoring systems, and safe entry and exit from supported excavations.
SWMS variants reference your state’s WHS legislation. Instant download after payment.
Trench shoring covers the shoring and support of trenches and excavations — installing trench boxes, shields, shoring and ground support to prevent the collapse of a trench during excavation and work. It addresses the defining hazard of civil excavation: trench collapse, which occurs quickly and is a leading cause of fatality, alongside the powered mobile plant, the underground services, and access to the trench. This document is written on the basis that trench shoring is carried out with the collapse-prevention, plant, services and access controls in place, and a SWMS where the trench exceeds 1.5 metres.
Trench shoring is carried out as construction work in connection with the excavation requirements, with the trench collapse prevented by shoring, benching or battering and trench boxes or shields, the powered mobile plant operated safely, the underground services located and avoided, and safe access provided. Because the work is in or near a trench deeper than 1.5 metres and in an area of powered mobile plant movement, it is high risk construction work. The collapse prevention, the plant, the services, and the access are the considerations. This document coordinates the collapse-prevention, plant, services and access controls so the trench shoring is carried out safely.
Hazards identified
9 hazards covered, sorted by priority.
Fatal engulfment and crush from trench collapse
Crush and run-over from the excavators and plant
Service strike on gas, electrical or water services
Falls of people or plant into the trench
Crush installing and removing the shoring and trench boxes
Collapse from inadequate or failed ground support
Collapse and falling material from spoil near the edge
Entrapment from inadequate access and egress
Collapse from water ingress and unstable ground
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Engineering: prevent trench and excavation collapse — the leading cause of fatality in excavation — by shoring, benching or battering the excavation, using trench boxes or shields, to a geotechnical assessment where required, because a collapse occurs quickly and can bury or crush a worker.
- 2Engineering: use the road and civil plant — pavers, rollers, profilers, graders, rigs and trucks — safely to the plant requirements and the manufacturer's instructions, with guarding, pre-operational checks, competent operators and the plant maintained.
- 3Administrative: obtain the essential services information before excavating — through Before You Dig Australia for underground assets and the Look Up and Live information for overhead assets — and locate, identify and avoid or isolate the services, because striking a gas, electrical or water service can cause explosion, electrocution or flooding.
- 4Engineering: provide safe access and egress to the excavation, secure the excavation from unauthorised access and from people and plant falling in, and keep spoil and plant back from the edge.
- 5Engineering: install and remove the shoring and trench boxes with the excavator and a procedure, keeping workers out of an unsupported trench, to a geotechnical assessment where required.
- 6Engineering: keep spoil and materials back from the edge, and manage water ingress and unstable ground.
- 7Administrative: because the work is in or near a shaft or trench with an excavated depth greater than 1.5 metres, prepare a SWMS for the high risk construction work before it commences, with the ground-support and access controls implemented.
- 8Administrative: because the work is carried out in an area in which there is movement of powered mobile plant, prepare a SWMS for the high risk construction work before it commences, with the pedestrian and plant separation implemented.
- 9Administrative: all workers must hold a valid White Card (General Construction Induction Training, CPCCWHS1001), with the plant tickets, traffic control accreditation, confined space, and other competencies required for the work.
- 10Administrative: conduct a pre-start toolbox talk covering the day's work, identified hazards, the traffic and plant movements, required PPE and emergency procedures, and record attendance in the consultation section.
- 11Administrative: consult workers and any health and safety representatives on the work and its risks, record the consultation, and keep this document available at the workplace.
- 12PPE: high-visibility clothing to AS/NZS 4602.1, eye protection, hearing protection where required, gloves appropriate to the task, and Class I or Class II safety footwear with protective toecap to AS/NZS 2210.3.
- 13Administrative: review and update this SWMS whenever the work scope changes, after any incident or near miss, when a worker or health and safety representative raises a concern, when new hazards are identified, or at minimum every 12 months.
- 14Administrative: confirm the work is completed safely, the excavation, plant and area are left in a safe condition, and the site is secured.
Applicable Codes of Practice
The controls for the excavation and trenching, including ground support, services and access.
Controls for the road and civil plant, rigs, rollers and pavers used in the work, including guarding and safe operation.
Obtaining the underground and overhead essential services information before excavating or working near services.
The general construction work duties for the civil road work, including the SWMS and principal contractor duties.
The risk management process and hierarchy of controls applied to the hazards of the work.
High-Risk Construction Work triggered
The work is in or near a trench with an excavated depth greater than 1.5 metres, which is high risk construction work requiring a SWMS before the work commences, with ground support against collapse.
The work is carried out in an area in which there is movement of powered mobile plant such as excavators, which is high risk construction work requiring a SWMS before the work commences.
This is civil construction work that, in the circumstances described, is high risk construction work — involving in or near a shaft or trench with an excavated depth greater than 1.5 metres; in an area at a workplace in which there is movement of powered mobile plant — so a SWMS must be prepared before the work commences, kept readily accessible, reviewed as necessary, and given to the principal contractor if one is appointed. The work is carried out in connection with the relevant construction, excavation, traffic, plant and other requirements, with the controls for the specific hazards applied. A failure in this work can cause a fatal trench collapse, traffic, plant, fall, gas or other serious injury, and breaches of the relevant legislation and the primary duty of care under the model WHS Act are actively enforced, with offence categories running from failure-to-comply through to reckless conduct, and the most serious breaches carrying imprisonment for individuals. Body-corporate maxima are substantial and indexed; the current maximum follows the prevailing schedule of the responsible regulator.
Who this is for
- →Excavation and civil crews installing trench support.
- →Civil and excavation contractors.
- →Civil construction and utilities businesses.
- →PCBUs requiring trench excavation and shoring.
- →PCBU safety managers and supervisors coordinating the collapse-prevention, plant and services controls.
What you receive
- ✓Editable Microsoft Word document (.docx) fully compatible with Microsoft Word 2016 and newer, Google Docs, and LibreOffice Writer.
- ✓Title page with editable fields for PCBU name, ABN, site or project address, work description, principal contractor details, and document revision date.
- ✓Hazard register with the trench shoring hazards — each with a documented consequence, inherent risk rating on a 5x5 likelihood-consequence matrix, hierarchy-of-control measures, and residual risk rating.
- ✓Trench shoring prompts referencing the excavation Code of Practice, a collapse-prevention and ground-support section, a services section, and a plant and access record.
- ✓Licensing and competency prompts for the plant, traffic control, confined space and other work, and a plant pre-operational and inspection checklist where relevant.
- ✓Worker consultation record per the model WHS Act consultation duty and a worker sign-on register (blank, expandable).
- ✓Applicable legislation and Codes of Practice schedule pre-populated for the model WHS jurisdiction with a state-variance reference table covering the harmonised states, plus Victoria.
- ✓Emergency procedure template and a revision log.
Worked example
A civil crew is engaged to shore a trench during excavation. The trench collapse is prevented by shoring, benching or battering the excavation and using trench boxes or shields, to a geotechnical assessment where required, because a collapse occurs quickly and can bury or crush a worker. The excavators and plant are operated safely. The underground services are located through Before You Dig Australia, identified and avoided. Safe access and egress are provided, and the trench secured from unauthorised access and from people and plant falling in. The shoring and trench boxes are installed and removed with the excavator and a procedure, keeping workers out of an unsupported trench. Spoil and materials are kept back from the edge, and water ingress and unstable ground managed. Because the trench exceeds 1.5 metres and the work is in an area of powered mobile plant movement, a SWMS is prepared for the high risk construction work. The shoring is installed, and the records retained.
Related legislation
- Model Work Health and Safety Act — primary duty of care; the duty to consult workers; the reckless-conduct offence; and notifiable-incident provisions, as enacted in each jurisdiction.
- Model Work Health and Safety Regulations — the construction work, excavation, plant, traffic, confined spaces and falls provisions, and the Section 291 high risk construction work and SWMS duties, as enacted in each jurisdiction.
- The construction work, excavation work, confined spaces and falls Codes of Practice, the traffic management guidance, and the relevant standards such as AS 5100 for bridges and AS 4678 for retaining structures, are called up by the relevant safety legislation for the civil road work.
- Essential services information is obtained through Before You Dig Australia for underground assets and the Look Up and Live information for overhead assets before excavating; plant operation, traffic control and confined space work require the relevant licences, accreditations and competencies.
- Victoria operates under the Occupational Health and Safety Act 2004 and the Occupational Health and Safety Regulations 2017, with the construction, excavation, plant and high risk construction work provisions applying in place of the model instruments.
Frequently asked questions
Why is trench collapse the defining hazard?
Trench collapse occurs quickly and can bury or crush a worker, and is a leading cause of fatality in excavation, so it is prevented by shoring, benching or battering the excavation and using trench boxes or shields, to a geotechnical assessment where required. Preventing trench collapse is the defining purpose of trench shoring.
When is a SWMS required for trench work?
A SWMS is required before the work commences where the work is in or near a trench with an excavated depth greater than 1.5 metres, which is high risk construction work, and where the work is in an area of powered mobile plant movement. The trench depth and the powered mobile plant trigger the high risk construction work requirements.
How are underground services protected?
The essential services information is obtained through Before You Dig Australia, and the underground services located, identified and avoided, because striking a gas, electrical or water service can cause explosion, electrocution or flooding. Locating and avoiding underground services prevents a service strike during excavation.
How are workers kept safe installing shoring?
The shoring and trench boxes are installed and removed with the excavator and a procedure, keeping workers out of an unsupported trench, because an unsupported trench can collapse. Keeping workers out of the unsupported trench and installing the support from outside prevents a collapse injury.
Who carries out trench shoring?
Trench shoring is carried out by competent civil crews in connection with the excavation requirements, with the collapse-prevention, plant, services and access controls, and a SWMS for the high risk construction work. The trench is shored with the collapse, plant and services managed.