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What is Deep Excavation?
Deep excavation is an excavation that goes down more than 4.5m (or 15ft) deep into rock or soil.
Excavations can range from shallow to deep and can be general or focussed. The depth of an excavation is dependent on the requirements of the excavation that is being carried out.
An example of shallow excavation would be for laying electrical wires, whereas deep excavation projects would typically be for the foundations of large offices or housing blocks. Deep excavations are defined as being deeper than 4.5 metres.
Deep excavations are much more difficult to plan than shallow excavations, and they require much more time and resources. Deep excavations should only be conducted by trained and skilled professionals, such as Quinn Developments.
How Is a Deep Excavation Carried Out?
When we carry out a deep excavation, we need to consider the ground conditions and perform a full site assessment. Deep foundations can impact surrounding structures and any construction project needs to have a carefully considered approach and perform a thorough risk assessment.
Although every site is different, a deep excavation usually involves the following steps:
Site Investigation: Before any excavation work begins, we carry out a thorough assessment of ground and soil conditions. This helps us decide on the best excavation method and any specific precautions we need to take.
Planning & Monitoring: Each project is unique, so we tailor our planning to suit the job. At Quinn Developments, we take great care to develop detailed deep excavation designs. This allows construction workers to use the correct method of excavation for the particular project.
Mechanical Excavation: We use heavy machinery such as hydraulic excavators and backhoes to remove soil in layers (often called “lifts”). This step-by-step approach allows us to install or adjust support systems as we dig deeper.
Reinforcement & Shoring: Reinforcing and supporting the excavation walls is critical. Methods like shoring, the use of retaining walls, or bracing systems (e.g., steel struts) keep the excavation stable and protect our team. At Quinn Developments, we carry out regular health and safety checks to maintain our high standards and help prevent cave-ins.
Dewatering (if required): Some sites require water to be pumped out before or during excavation. Well-placed pumps and systems ensure we can maintain a dry, stable work area for our excavation activities.
Final Excavation & Construction: Once the excavation is at the required depth, we smooth and prepare the base for whatever is next, whether it’s laying foundations, constructing an underground car park, or installing important infrastructure.
FAQs
How deep can you dig before you need shoring? 
Typically, an excavation trench over 1.5m in depth needs protection. This is unless the excavation is completed in secure stable rock. However, excavation projects under 1.5m can also be required to have reinforcements; it is dependent on the person in charge to make the decision.
When should excavations bQuinn developments specialise in groundwork and deep excavation. If you would like a free no no-obligation quote please fill out our contact form or call us on 0151 345 6551.e inspected? 
Excavations should be inspected once a day at the very least. If the excavation is over 2m in depth, an inspection is required before each work shift. An inspection is mandatory after an event the has or is thought to have impacted the stability or strength of the shoring or the excavation.
What are the greatest risks associated with excavations? 
The biggest risk to an excavation is a cave-in. Cave-ins are much more frequent than any other excavation related accident; Cave-ins are the biggest cause of fatalities with excavations. Other risks and hazards include hazardous atmospheres, falls and falling objects (tools, rocks etc.).
What does an excavation contractor/company do? 
An excavation company’s responsibilities include project planning, site preparation, trenching, grading, shoring, reinforcements and many other tasks. To help with the excavation heavy machinery is used; each piece of heavy machinery can only be operated by a trained person.
What is a grading? 
Grading is the process of flattening and smoothing a surface. In relation to deep excavation, grading is used for the foundations of buildings. A grader is a piece of heavy machinery that is used to flatten and smooth the surfaces.
Do Quinn Developments undertake Deep Excavation? 
Quinn developments specialise in groundwork and deep excavation. If you would like a free no no-obligation quote please fill out our contact form or call us on 0151 345 6551.
