A box system is a mechanical excavation support system used to create a protected working area within an excavation. Typically made up of two steel panels connected by adjustable struts, boxes are installed in excavations to help protect operatives working below ground level.
Unlike some excavation support systems that are designed to pressurise the ground, a box system acts as a protective shield within the excavation. They are designed to withstand ground pressure to provide a protected space for workers inside the excavation.
Box systems are generally lowered into the excavation using an excavator. They can be installed using either the dig and push technique, where the box is progressively installed by digging within the box and pushing down on the panels using the excavator, or by using the excavate and lower in place technique, where the excavation is pre-dug and the box is simply lowered into place.
The box panels are held apart by struts, which are adjusted to the required width, creating a safe working space between them. Depending on the scope of the works multiple boxes can be installed at once, or boxes can be repositioned as work progresses.
Box systems are commonly used for:
By providing a protected workspace and allowing services such as pipes, ducts and cables to be installed safely, boxes are one of the most widely used excavation support solutions in the construction and utilities sectors.
Box systems are available in a variety of sizes and configurations to suit different excavation depths, widths and ground conditions. Depending on the application, contractors may choose from traditional Trench Boxes, Drag Boxes, Utility Trench Boxes, Manhole Boxes, High Clearance Trench Boxes, Aluminium Trench Boxes or MGF’s GRiPSHORE and GRiPSHORE+ Trench Boxes.Â
Before selecting a box, there are several important questions to ask.
What Is The Excavation Being Used For?
While ground conditions play a major role in box system selection, it’s equally important to consider how the excavation will be used and what needs to be installed within it.
Questions to consider include:
Understanding the installation requirements helps determine the most appropriate trench support system. For example, projects involving large diameter concrete pipes may require a High Clearance Trench Box, chamber construction may benefit from a Manhole Box, and linear installation works may be better suited to a Drag Box.
What Are The Ground Conditions?
Ground conditions are one of the most important factors when choosing a box, as they influence the level of support required within the excavation. You should consider:
While stable ground conditions are required if installing box systems using the excavate and lower in place technique, if you are using a dig and push technique and the ground type isn’t very weak, such as very soft clays and peats, then a box system can be used. Larger excavations or more demanding environments may require a more specialist solution.
How Deep And Wide Is the Excavation?
The dimensions of the excavation will influence the size and type of box required. Excavation depth affects the maximum loading acting on the box support system, while excavation width determines the working area available within the trench. It is important to ensure the selected system provides sufficient working space for both operatives and the asset being installed.
What Size Pipe Or Asset Is Being Installed?
The size of the pipe, tank or other infrastructure asset can influence box selection. Larger installations often require greater clearance beneath the struts and additional working room within the excavation. Considering the installation requirements at the planning stage helps avoid delays once work begins.
Will The Excavation Progress Along A Route?
Many utility and pipeline projects involve trenching operations that move progressively along a route. Where this is the case, a trench support system that can be repositioned quickly and efficiently may offer significant productivity advantages throughout the project.
MGF offers a range of boxes designed for different applications, excavation sizes and ground conditions.
Traditional Trench Boxes are typically the go-to solution for everyday excavation works. While specialist Trench Box systems such as Utility Trench Boxes and High Clearance Trench Boxes are designed for specific applications, the traditional range of Trench Boxes offer the flexibility to support a broad range of trenching projects. Generally installed using the dig and push technique, in depths of up to 7m, traditional Trench Boxes are quick and easy to assemble and use, and are often the most practical and economical choice for standard applications.
While Trench Boxes provide 2-sided excavation support, open ends of boxes can be closed off using Trench Sheets or Endsafe panels to provide 3-sided and 4-sided excavation support.
Best suited for:Â
Manhole Boxes are a four-sided mechanical excavation support system designed for chamber construction and the installation of precast concrete structures. By providing support on all four sides of the excavation, they are particularly suited to projects where a standard two-sided trench box may not provide sufficient protection or access.
Manhole Boxes are traditionally assembled into a square configuration with panels ranging in length from 2.0m up to 5.2m. They’re installed using the dig and push method to depths of up to 5.8m.
Best suited for:
Drag Boxes are specifically designed for projects where excavations progress along a route, making them a popular choice for utility and pipeline installation works. Unlike other trench support systems that may need to be lifted and repositioned frequently, a Drag Box can be ‘dragged’ through a pre-excavated trench as work advances, helping to maintain productivity on linear .
Drag Boxes are designed to act as a shield and should ideally not be side loaded by the ground, to ensure the system can be easily dragged. Due to this, Drag Boxes should only be used in suitably stable ground that will stand to the excavated depth for the anticipated duration of the works.
Consideration must be taken to the overall weight of the Drag Box and the capacity and reach of the excavator.
One Drag Box can be used for the entire trench run, reducing handling time and minimising interruptions during installation and, as such, they’re an economical/cost effective option for customers.
Best suited for:Â
Utility Trench Boxes are designed to be installed using the excavate and lower in place technique and not driven into the ground like traditional Trench Boxes.
Utility Trench Boxes provide additional working space below the high clearance, bolted struts, making them ideal for utility installation, maintenance and repair projects, requiring excavations up to 2.5m in depths and 4.0m in width. Their large working area gives operatives better access when installing, connecting or repairing underground services, especially when multiple Utility Trench Boxes are installed in a run.
Best suited for:
High Clearance Trench Boxes are designed for projects involving large-diameter pipes, tanks and substantial infrastructure assets. The range includes 7.0m long base and top panels, enabling maximum depths of 5.0m and trench widths of up to 5.9m. The adjustable, high clearance struts provide increased space beneath the struts, of up to 3.0m, in addition to generous clearances of 6.0m between the struts, making the installation of larger assets easier and more efficient.
Best suited for:
Aluminium Trench Boxes provide a lightweight and practical excavation support solution for shallow utility works, where ground movement is considered non-critical. Their reduced weight makes them easier to handle and install than traditional steel systems, meaning they are particularly useful on smaller projects and restricted-access sites.
They are designed to be installed using the excavate and lower in place technique to depths of up to 2.4m, and should not be driven into the ground.
Best suited for:
GRP and steel reinforced GRP Trench Boxes are lightweight two-sided excavation support systems, designed to provide temporary support to shallow trenches for the safe installation and maintenance of utilities.
Both systems feature lightweight components, that can be assembled by hand and in the case of GRiPSHORE® GRP Trench Boxes, can be installed by hand without the need for an excavator. This saves time onsite and enables GRiPSHORE® systems to be easily transported by hand and installed in environments that would be restrictive for heavier steel box systems.
While GRiPSHORE+ Trench Boxes use lightweight adjustable steel struts, GRiPSHORE® GRP Trench Boxes utilise lightweight hydraulic struts, which can be installed into the trench, by hand, and pressurised to make the trench safe prior to entry.
Designed to be installed using the excavate and lower in place technique, GRiPSHORE® & GRiPSHORE+ systems require ground conditions that are generally self-supporting in the short term. GRiPSHORE® Trench Boxes are suitable for use in depths of up to 2.2m, while GRiPSHORE+ Trench Boxes can be used in depths of up to 2.8m.
Best suited for:
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Choosing the Right Box System
Choosing the right box starts with understanding the ground conditions, excavation dimensions and installation requirements of your project. By considering these factors early in the planning stage, contractors can select the most appropriate excavation support system for safe and efficient project delivery.
With a comprehensive range of box systems available for utility installation, pipeline construction and chamber works, MGF can help contractors identify the right solution for their excavation requirements.
To find out more about our products, visit: Our Product Range or email support@mgf.co.uk.
Whether you have a question, need a quote, or want to discuss a project, our dedicated team is ready to assist you.
