Soil Mixing Success for Nar Ouse Enterprise Zone, King's Lynn

This project involved soil mixing to prepare the ground for new service roads and infrastructure as part of the business park and industrial estate construction.

Main Contractor: 
Octavius 

GGBS Supplied: 
3970 Tonnes

Binder used in %: 
50/50

Project Duration: 
12 Months (Starting End of 2022) 

Total Cost: 
£3.5 million 

 Challenges: 

• Unstable Ground: The site had deep layers of peat that lacked the strength to support road and infrastructure construction. 

• Inconsistent Soil Composition: Historical waste tipping activities on-site led to varied soil consistency, presenting additional challenges for stabilisation. 

The Solution: 

The deep soil mixing method was proposed to address the unstable ground conditions, involving a combination of soil-mixed slabs and soil-mixed columns. Key features of the solution included: 

• Depth: Ground treated to depths of 7.0 to 7.5 metres for maximum stability. 

• Binder Composition: Adjustments were made to binder composition and water content to ensure optimal soil stability and strength. 

• Environmental Considerations: No soil was removed to landfill, reducing environmental impact and vehicle movements on site. 

Key Achievements: 

• Stability and Strength: The soil’s load-bearing capacity was increased, supporting the construction of service roads, embankments, and future infrastructure. 

• Low Environmental Impact: The solution was designed to minimise carbon emissions, with in-situ soil mixing requiring no excavation or transportation of waste material. 

• Utility Protection: Soil mixing was employed to protect sensitive utilities such as gas mains and drainage systems, thanks to its low-vibration properties, with vibration levels well below National Grid standards. 

Advantages of Soil Mixing: 

• Increased Stability & Strength: The soil’s structure was significantly enhanced for long-term support of roads and infrastructure. 

• Cost Efficiency: Soil mixing reduced overall project costs as less construction time was needed. 

• Low Vibration Impact: With minimal vibration, soil mixing posed no threat to nearby utilities and structures, allowing for construction as close as 200mm from sensitive areas. 

• Environmentally Friendly: No requirement to excavate and cart away. 

• Improved Health & Safety: Fewer vehicle movements on site reduced potential hazards and increased overall safety. 

Conclusion: 

The soil mixing technique provided a cost-effective, environmentally friendly, and highly effective solution for ground improvement on the Nar Ouse Enterprise Zone. The successful completion of the project ensured stable foundations for the new roads and infrastructure while minimising the environmental impact and safeguarding utilities.