Vacuum Trench Excavation in Richmond

Scope of Works

When Thames Water required trenching works for new services, the site presented a unique set of challenges. The use of a standard lorry-mounted vacuum excavator was ruled out due to its weight, which posed a risk to existing underground services. In addition, a Tree Preservation Order severely restricted access around the site perimeter. Due to the trench dimensions and the risks associated with working alongside an open excavation, all personnel were required to maintain a minimum distance of 1.0 m from the trench edge.

To meet these high demands, Castle & Pryor delivered a smart, lightweight solution tailored to the constraints of the site. Through innovation and engineering experience, the works were completed safely, on time, and within budget, reinforcing our reputation for solving complex problems where conventional methods fall short.

What We Did

Castle & Pryor was appointed to excavate a 30.0metre long trench, 1.0 metre wide and 1.0 metre deep, within a highly constrained environment containing live underground services. Safety, precision, and minimal disruption were critical.

To achieve this, we deployed one of our compact tracked vacuum excavation (Vac-Ex) machines, allowing material to be removed safely around live cables. Drawing on our in-house engineering capability, we designed and fabricated a bespoke attachment for the Brokk 160 robotic unit. This innovation enabled the Vac-Ex suction hose to be operated remotely from a safe distance of a minimum of 1.5 metres, eliminating risk to personnel, protecting critical infrastructure, and maintaining productivity despite the severe access restrictions.

This project highlights Castle & Pryor’s ability to think differently, engineer bespoke solutions, and deliver safe, efficient outcomes in the most challenging environments. A prime example of how innovation and safety can go hand in hand on today’s complex work environments.