Addressing Subsidence Issues in Residential Properties
The Challenge
The client, having recently purchased a property, encountered substantial subsidence at the rear of the building, primarily due to construction over a layer of peat. Traditional stabilisation methods, such as concrete underpinning, were deemed unviable for this unique situation, necessitating an innovative approach. Key concerns included:
- Weak Peat Layer: The unstable peat layer was causing significant instability, leading to potential risks for the existing structure.
- Potential Damage During Remediation: There was a considerable risk of further damaging the property during the remediation process, which needed to be mitigated.
- Need for a Reliable, Long-Term Solution: The client required a dependable solution to enhance the ground’s bearing capacity and prevent future subsidence.
Why Ground Stabilisation?
After evaluating various options, TSM determined that a polymer injection system would provide the most effective solution. This method offered several advantages over conventional techniques:
- Minimal Disruption: The polymer injection process minimised disruption to the property and surrounding areas, allowing the client to maintain normal operations during the remediation.
- Enhanced Soil Strength: This method effectively converted loose peat into a more stable material, significantly improving ground stability.
- Quick Application: The rapid application of the polymer allowed for swift remediation without extensive excavation, reducing the overall project timeline.
The Solution: Polymer Injection
TSM employed a structural polyurethane ground stabilisation geopolymer resin, which was injected to reinforce the soil beneath the foundations. The process involved several key steps:
- Driving Injection Lances: TSM installed injection lances to a depth of 4 meters around both the perimeter and internal foundations of the property. This ensured that the resin would reach the most affected areas.
- Resin Injection: The geopolymer resin was injected through the lances, ensuring thorough penetration into the ground. This process was carefully monitored to ensure effectiveness.
- Incremental Extraction: The lances were extracted in 150mm increments to achieve continuous and effective placement of the stabilising agent, ensuring an even distribution throughout the affected soil.
This method ensured a robust and lasting solution to the subsidence issue, effectively stabilising the ground beneath the structure.
Managing Site Sensitivity
Given the complexities associated with subsidence repair, TSM implemented careful planning to minimise disruption:
- Real-Time Monitoring: Ground movement was closely monitored throughout the project, ensuring that the structural integrity of the property was maintained at all times.
- Expert Coordination: TSM worked closely with the client, providing regular updates and ensuring that all aspects of the project were executed efficiently and effectively.
Environmental Considerations
The chosen polymer injection method was environmentally friendly, offering several benefits:
- Non-Toxic Materials: The materials used posed no risk to the surrounding soil or water systems, thereby safeguarding the local environment.
- Minimal Waste Generation: The process generated minimal waste, with excavated materials classified as non-hazardous, aligning with best practices for environmental safety.
This approach not only addressed the immediate structural concerns but also demonstrated TSM’s commitment to environmental stewardship.
Ensuring Structural Integrity
Throughout the project, TSM conducted regular assessments to ensure that ground movement remained within acceptable limits. This proactive approach confirmed that the property’s stability was maintained effectively, providing peace of mind to the client.
