Restoring Ground Support at a Major Food Manufacturing Facility

The facility relies on continuous, high-volume food production, making the performance and stability of the production floor critical to daily operations.

The oven production area had experienced significant differential settlement across the concrete slab. A pre-works survey identified level variations of up to approximately 100mm throughout the most affected sections, with a noticeable low point through the centre of the area.

The settlement had resulted in visible floor deformation, minor cracking and operational impacts within the production space.

Existing drainage infrastructure and multiple underground services added further complexity. Sewer, water, stormwater and power services were located within and around the treatment area, requiring careful planning and monitoring before and during drilling and injection.

Given the operational importance of the facility, the works needed to be completed within a limited shutdown window. The solution needed to improve ground support, reduce slab movement and recover floor levels where achievable, while maintaining the existing drainage falls designed into the floor system.

Before drilling commenced, the client arranged for underground services to be located using CCTV inspections and ground-penetrating radar scanning. Sewer, water, stormwater and power services were identified within and adjacent to the work area.

Injection points were installed across the treatment area in a grid pattern at approximately 1200mm, with known services carefully avoided during drilling. The concrete slab was found to be approximately 180mm thick.

Mainmark used Teretek® resin injection to complete the ground improvement and controlled re-levelling works.

The treatment was delivered across four stages:

The first stage involved installing injection rods to approximately 1.5m depth to create an undersealing layer beneath the slab and address shallow voiding. Extensive voiding and saturated ground conditions were encountered during this stage, requiring greater resin volumes than originally anticipated to achieve refusal and produce a measurable slab response.

The second stage involved intermediate ground improvement at approximately 2.0m depth. This stage focused on additional void filling and the consolidation of weakened subgrade materials beneath the slab.

The third stage involved controlled level recovery at approximately 2.5m depth, with targeted injections completed throughout the most affected settlement zones. Floor levels were continuously monitored using laser and water level systems, with injections carried out incrementally so the slab response could be carefully controlled.

The final stage involved deep consolidation at approximately 3.0m depth. This created an additional treatment layer beneath the slab and further improved support conditions within the most affected areas.

Throughout the lifting process, the on-site engineering representative monitored and adjusted the production equipment to accommodate the changing slab levels.

The completed treatment filled significant subsurface voids, improved support conditions beneath the slab, densified weakened subgrade materials and reduced differential settlement across the treatment zone.

The works successfully re-levelled the slab by up to 98mm in the most affected areas. The post-treatment survey showed a substantially more uniform floor profile compared with the pre-treatment condition, while maintaining the functional drainage falls required within the production area. The previous low point through the centre of the oven area was significantly reduced, and floor levels became more consistent across the treatment zone.

CCTV inspections were completed before and after the injection works. The final inspection confirmed that the monitored drainage lines had not been damaged during the treatment. The work area was cleaned upon completion, and a final level survey was undertaken to verify the achieved outcome. The project demonstrated Mainmark’s ability to deliver specialist ground engineering works within a complex operational industrial environment. By completing the works during a long weekend shutdown, Mainmark helped the client address slab movement and loss of support beneath a critical production area without the disruption and downtime associated with slab replacement.