The Infrastructure sector:

Highways A127 deep depth GPR & ground remediation

Project case study for the A127 highway

The A127 is a two-lane, 7km long, all-purpose trunk road that carries high volumes of traffic through Essex. Restek provides tailored and individual ground remediation solutions, as no two projects are the same. This enables project programmes to be reduced, which is more cost effective for the client & offers a long-term performance solution of up to 20 years. The A127 project was subject to an LGF grant, so it was vital that the essential maintenance work was carried out efficiently and within budget.

Restek surveyed approximately 32,000m2 of carriageway using our unique deep depth GPR system. This identified issues beneath the carriageway pre- ground remediation & validated the resin injection and ground stabilisation process after the remediation work had been carried out. Our deep depth GPR system plots a clear image of every issue below ground, allowing our engineers to understand the make up of the interlayers below the carriageway surface.

Restek’s specialist remediation team utilise the data to assist with specifying and designing a value-engineered solution that is not just robust but also prevents potential issues from arising in the future.

On the A127 project, our deep depth GPR data revealed that essential modifications to the proposed standard specification were required to achieve the project goals. Restek’s unique three-tiered approach allowed us to modify and adapt the original project specification to meet the clients’ expectations and requirements.

Restek created a bespoke, value-engineered solution for the A127 project, to ensure the budget was maximised, allowing the client to include an additional scope of work that would not have been possible with a standard approach. Restek prioritised reducing the risk of mitigation through regular communication/collaboration with the client, ensuring the successful completion and on-time delivery of the project.

Restek’s post remediation process including deep depth GPR surveying and independent testing carried out by the client, this has resulted in an expected lifecycle extension to the carriageway of up to 30+ years. This lifecycle extension means no additional budget spending will be necessary in the short term, and has eliminated the costly exercise of removing/replacing complete sections of carriageway.

The A127’s remediation success has allowed the client to push forward with their plans for expansion of the network & has helped to encourage growth within the local region.

Restek’s advanced GPR software presents the data in a clear 2D & 3D format which is easy to evaluate and interpret and is bespoke to each project. No matter if your sector is Road, Rail or Residential, Restek will be able to provide you with customised project data tailored for your scheme.

A127 Project & Ground Remediation Details:

• The carriageway was constructed from original concrete slabs overlaid with asphalt

• The reason for remediation was due to large volumes of traffic and HGVs causing settlement and hydro-fracture

• The scheme brief was to stabilise the pavement. This was the largest project of it’s kind in the UK consisting of 1181 bays at 27.9m² each

• On average, 13 bays were completed during each 8 hour night closure

• Restek’s GPR, compaction and permeation grouting services were used to remediate the ground beneath the highway

• Our GPR surveys identified voids and loosely compacted sub-base beneath the carriageway

• GPR data showed a range of depths of injections were required, with many being much deeper than originally specified

• We used our deep depth GPR system to verify the remediation works success, we then communicated the results to the client

• The project was completed on budget, ahead of programme and the client was extremely happy with all aspects of the work carried out