Geotechnical Investigation and Remediation in Leytonstone

Lustre Consulting was appointed by Equans to undertake a Phase 2 Geotechnical Investigation and provide a Remediation Verification Report for the redevelopment of a site located on Sansom Road in Leytonstone, East London. The project involved the construction of a six-storey residential apartment building, including communal landscaped areas, on a site with significant geoenvironmental challenges due to its industrial history and contamination risks.

Geotechnical Investigation

The initial phase of our work focused on conducting a robust geotechnical investigation to assess the suitability of the site’s ground conditions for the proposed development. This stage involved:

• Exploratory Boreholes and Trial Pits: Boreholes and trial pits were strategically positioned across the site to assess subsurface soil and groundwater conditions. This allowed for a comprehensive understanding of the site’s geological profile.
  
• Soil Sampling and Laboratory Analysis: Soil samples were collected and tested for engineering properties such as strength, compressibility, and load-bearing capacity. This data informed the foundation design, ensuring it could support the multi-storey residential structure.
  
• Ground Gas Monitoring: Continuous monitoring wells were installed to evaluate the levels of methane and carbon dioxide on-site. The findings confirmed a negligible ground gas regime, classified as Characteristic Situation 1, meaning no additional gas protection measures were required.

The investigation’s findings informed key recommendations for foundation design and construction methodologies, ensuring structural stability and full compliance with building regulations.

Remediation Strategy and Verification

Due to the site’s industrial legacy, potential contamination risks were identified during earlier assessments. Lustre Consulting developed and implemented a tailored remediation strategy to address these risks effectively. Key steps in this process included:

• Removal of Asbestos-Containing Soils (ACS): Eight exploratory locations identified asbestos fragments or fibres in shallow soils. Remedial works involved a comprehensive site-wide excavation to remove all made ground, with visible asbestos fragments manually picked and segregated for safe disposal.
  
• Installation of Barrier Pipes: Soil data revealed elevated hydrocarbon levels unsuitable for standard polyethylene water pipes. Instead, barrier pipes were installed to safeguard the site’s potable water supply.
  
• Clean Cover System Installation: Following the removal of contaminated soil, a clean cover system comprising imported topsoil and subsoil was installed in landscaped areas. Verification testing ensured these materials met the chemical and physical suitability criteria for residential use.
  
• Waste Disposal and Validation: Hazardous soils, including asbestos-containing materials, were classified and disposed of at licensed facilities. Validation reports documented the removal process and confirmed compliance with waste management regulations.

Validation and Planning Compliance

To ensure the success of the remediation strategy, Lustre Consulting carried out multiple site visits to validate the implemented measures. Key activities included:

• Inspecting excavation works to confirm complete removal of contaminated soils.
• Verifying the suitability of imported soils and materials through laboratory testing.
• Documenting the placement of clean cover systems and other remedial measures.

The final Remediation Verification Report demonstrated that the site met all planning conditions imposed by Waltham Forest Council. This report was essential in certifying the site as safe for residential development and facilitating planning approval.

Site Investigation and Verification Impact

Lustre Consulting’s work on Sansom Road ensured the successful transformation of a challenging site into a safe, compliant, and sustainable residential development. By addressing contamination risks, verifying remediation measures, and supporting the geotechnical design, we provided Engie Regeneration Ltd with the necessary assurances to proceed with construction confidently.

For more information on how Lustre Consulting can assist with your geotechnical projects, visit our services page.