There's an alarming increase in excavation breaches in the UK according to BSG. Oliver Smith, Engineering Director at Groundforce, shares his view.
2025 delivered a sobering wake-up call to the UK ground engineering and construction sector. According to the latest data from the Building Safety Group (BSG), excavation breaches on construction sites surged by a staggering 50% between the first and second quarters of the year .
Based on over 7,000 independent site inspections, the findings suggest that despite our industry’s sophisticated understanding of soil mechanics and the proliferation of advanced shoring solutions, the gap between design intent and site reality is widening.
Excavation remains one of the most hazardous phases of any build, with the Health and Safety Executive (HSE) attributing approximately 15% of all construction-related fatalities to collapses. However, this recent spike demands more than a cursory review of safety processes; it requires a deep dive into the technical and systemic pressures currently facing geotechnical contractors.
The physics of failure
While it is tempting to attribute the spike in breaches to a seasonal increase in workload or shifting groundwater levels, the reality is more nuanced. Groundwater levels are typically highest in late winter, but the transition into summer leaves ground conditions highly variable - with residual saturation, softening, and changing drainage behaviour creating uncertainty in how the ground will perform.
However, the primary driver is rarely environmental alone. It is systemic. As an industry, we are building on increasingly constrained, "marginal" brownfield sites with incomplete data and tighter timelines.
Procurement routes often push specialist input later into the process, meaning temporary works solutions are frequently developed around fixed constraints rather than influencing them early. The issue is not the capability of the proprietary shoring systems - which are generally robust and designed to provide warning through deformation before failure - but how consistently they are applied and controlled under programme pressure.
The disconnect: design assumptions vs site reality
In ground engineering, the point of failure is rarely found in the structural design of the equipment itself. Instead, it occurs at the interface between design assumptions and site execution.
A temporary works design is only valid if the excavation depth, geometry, soil parameters, groundwater, surcharge loads, and installation sequence match what was assumed in the office. Ground Investigation (GI) data is effectively a snapshot of conditions at a particular point in time; in many cases, one or more of these parameters changes on-site without a formal engineering review. Once that happens, the excavation may no longer behave in line with the design intent, even if the support system appears to be in place.
The robustness of modern proprietary systems can ironically create a false sense of security. Because these systems are designed with inherent factors of safety and often show visible deformation before structural failure, site teams may perceive them as "forgiving" of deviations.
This is a dangerous misconception. Most excavation incidents don’t happen because the equipment suddenly fails, but because the excavation has already moved beyond the conditions it was designed for, and that change hasn’t been recognised or controlled.
Reversing the trend
To reverse this trend, the industry must move away from treating shoring installation as a routine activity and return to viewing it as a critical engineering stage. Failures are frequently linked to specific deviations: incorrect spacing, incomplete installation, or allowing excavation to progress too far ahead of the support.
We do not necessarily need constant redesigns, but we do need a more realistic definition of the design envelope. Suppliers often design to a narrow brief to remain competitive. It is the responsibility of the contractor and the Temporary Works Coordinator (TWC) to define a realistic envelope at the outset, including credible worst-case conditions - such as groundwater at ground level or maximum possible surcharges - rather than a single "best-case" snapshot.
If I could mandate only one change across UK sites, it would be a rigorous requirement to verify that site conditions match design assumptions before the first bucket hits the ground. Excavations should not proceed on the basis of a drawing alone. There must be a clear "hold point" where a competent person confirms that the geometry, soil, and loading are consistent with the engineer’s intent.
The cost of deviation
We must leverage technology to bridge the skills gap. Digital monitoring, such as proprietary load-monitoring sensors on hydraulic struts, provides real-time data that human observation might miss. Beyond visual checks, engineers must look for indicators that the excavation is no longer behaving as assumed. This includes subtle ground movement, softening of the formation, or changes in load distribution such as poor seating of components.
Consider an urban basement excavation where the design assumed a specific surcharge from nearby plant machinery. On-site, due to space constraints, a heavier crane was positioned closer to the excavation edge than planned. Because the "design envelope" hadn't accounted for this deviation, the shoring system began to show subtle signs of distress, including tension cracking and unexpected water ingress.
In this instance, early recognition of these indicators allowed for a dynamic review and the installation of additional lateral support. Had the site team relied on the perceived “robustness” of the equipment without questioning the change in parameters, the 50% breach statistic would likely have claimed another project.
A safer future
Reversing the rise in excavation breaches requires more than incremental equipment upgrades; it demands a fundamental shift in site culture and a commitment to deeper collaboration between contractors and specialist suppliers.
While proprietary systems are a formidable line of defence, they are not a substitute for rigorous engineering oversight. By narrowing the gap between the design office and the trench, and ensuring the TWC is empowered to halt works when reality drifts from design, we can ensure that a “zero-failure" site culture becomes an industry standard, rather than a moving target.