What is Trench Shoring?
Trench shoring is a temporary support system used to prevent the walls of an excavation from collapsing while work is carried out below ground. It is one of the most effective methods of protecting workers during excavation projects and plays a critical role in maintaining safe working conditions on construction and civil engineering sites.
Trenches are defined as excavations that are deeper than they are wide. They are commonly used for installing utilities such as water, gas, electricity and telecommunications infrastructure, as well as drainage and sewer systems. The deeper a trench becomes, the greater the pressure exerted by the surrounding soil, increasing the risk of collapse.
Even a relatively shallow trench can become unstable due to changing ground conditions, heavy rainfall, nearby traffic, or the weight of excavated material placed too close to the edge. Without adequate support, trench collapses can occur suddenly and without warning.
Because of this, it's incredibly important that trenches are excavated and supported safely, ensuring everyone working within the excavation is protected throughout the project.
There are many different methods of trench support used across the construction industry, but trench shoring remains one of the most effective. Unlike some protective systems designed to safeguard workers if a collapse occurs, trench shoring actively supports the excavation walls to help prevent collapse in the first place. Combined with its versatility and relatively quick installation, trench shoring has become a trusted solution for projects of all sizes.
Why Do Trenches Collapse?
Understanding why trenches fail highlights the importance of selecting the correct support system. Common causes of trench collapse include:
- Loose or unstable ground conditions
- Heavy rainfall or water ingress
- Vibrations from nearby traffic or construction plant
- Spoil heaps placed too close to the trench edge
- Excavating too steeply without adequate support
- Additional loads from nearby buildings or machinery
Ground conditions can change quickly throughout a project, making regular inspections and appropriate excavation support essential.
Different Types of Trench Shoring
There are three main types of trench shoring materials, steel, aluminium and timber, which can be installed using either hydraulic or pneumatic technology.
Hydraulic aluminium shoring tends to be the preferred method for modern construction, as its benefits include being light enough to be installed by just one person and being easily adaptable to suit various trench depths and widths.
Additionally, hydraulic shoring can be installed without the need for manual interaction, which makes it the safest shoring type. However, pneumatic shoring offers increased stability, achieved by using underpinning to reinforce the shoring struts.
You can find out more about the different types of shoring.
How Does Trench Shoring Work?
Trench shoring works by applying controlled pressure against the excavation walls, counteracting the natural forces that cause soil to move into the trench. By stabilising the trench sides, shoring creates a safer working environment while allowing operatives to install or repair underground services.
The type of support system selected will depend on factors such as trench depth, soil conditions, groundwater, available working space and the duration of the project. For many excavations, trench boxes provide a practical and efficient solution for protecting operatives while work is carried out below ground.
Explore our range of trench boxes to find the right solution for your project.
When is Trench Shoring Required?
The need for trench shoring depends on the depth of excavation, ground conditions and the findings of a site-specific risk assessment.
In the UK, excavation work should always be planned, supervised and carried out by competent persons in accordance with current health and safety guidance. Wherever there is a risk of the excavation sides collapsing, suitable support should be provided.
Factors influencing whether trench shoring is required include:
- Excavation depth
- Soil type and stability
- Groundwater levels
- Nearby roads, buildings or structures
- The weight of plant or equipment operating close to the excavation
- Project duration
Selecting the correct support system at the planning stage helps minimise delays, improve productivity and maintain a safe working environment.
Installation Safety Requirements
Because shoring is so vital for securing the safety of a trench environment, installation must be carried out correctly.
Before excavation begins, contractors should assess ground conditions, identify underground services and ensure the appropriate trench support system has been selected.
During installation:
- Install shoring progressively as excavation advances
- Inspect equipment before use
- Ensure components are installed in accordance with manufacturer guidance
- Keep excavated spoil away from the trench edge
- Regularly inspect the excavation for signs of movement, water ingress or damage
Excavations should also be inspected following adverse weather, heavy rainfall or significant ground vibration, as these conditions can affect trench stability.
Find the Right Excavation Support Solution
Not sure which trench support solution is right for your project? YourSolution helps you quickly identify a suitable Groundforce standard solution based on your excavation requirements. If a standard solution isn't available, our technical team will review your project and provide expert guidance with YourSolution+.
Start your assessment with YourSolution or contact our team to discuss your project today.