The Deepcar development near Sheffield represents a major regeneration initiative on land formerly occupied by mining and heavy industrial activities. The site is characterised by deep made ground, highly variable fill materials, and the presence of historic mine workings, all of which contributed to complex and challenging geotechnical conditions.
As part of the transformation into a new residential community of approximately 400 homes, four major segmental retaining walls were constructed, forming critical elements of the site infrastructure. Some of these walls reach heights of up to 9 metres, representing significant engineering structures designed to accommodate both geotechnical and construction requirements.
Due to the poor load-bearing capacity of the made ground and the need to control settlement, the taller walls were founded on ground improvement using rigid inclusions (RIs). These elements were specifically designed to enhance ground performance and mitigate differential settlement risks.
A Load Distribution Mattress (LDM), also referred to as a Load Transfer Platform (LTP), was installed above the rigid inclusions. This system comprised engineered granular fill reinforced with perpendicular layers of high-strength geosynthetic reinforcement, each providing tensile strengths in excess of 250 kN. The LDM ensured effective transfer of loads from the retaining wall foundations into the improved ground, promoting uniform settlement behaviour and improving overall structural reliability.
In addition to their primary retaining function, the walls were designed to support a piling working platform for the residential units constructed above, introducing additional loading and performance requirements.
To address construction-phase demands, temporary reinforcement layers were also installed above the wall structures. This reinforcement was specifically designed to withstand the stresses imposed by piling operations, ensuring stability and safety during the build process.
