Our company was contacted by representatives of the engineering department of the central office of the OKKO GROUP holding. The problem arose as follows: due to erosion by rainwater, the road surface sagged, and voids formed under the slab. This, in turn, created dangerous conditions for cars, equipment, staff, and visitors to the gas station.
Stage 1. The company’s specialists conducted an audit and a dynamic sensing survey. An analysis of the data obtained showed that the structure is based on soils that have different and uneven degrees of compaction. Voids were found under a concrete slab of 20-100 mm. Also, according to geodetic survey data, the excess of the surface of the pavement relative to the conventionally accepted mark of 0.000 ranges from -6 mm to – 275 mm.
In this case, if urgent measures are not taken, the erosion can progress, leading to even greater subsidence of the soil, damage to the coating, infrastructure and potential emergency situations.
Stage 2 . Based on the results of the survey, Geotechnical Engineering Systems LLC developed a project to strengthen the base (soil) of the fuel column foundation and strengthen the base of the concrete slab of the roadway.
Stage 3. To strengthen the foundation of the fuel dispenser, we used a system of Stati-Pile Ø60mm stackable micro-pads, using Stati-CAL technology. The piles were immersed to a depth of -9.0 m from the daytime surface (concrete slab of the roadway). This allowed the load to be shifted to denser soil layers.
The next step is to fill the voids under the concrete slab and restore full contact between the slab and the soil. For this purpose, gelocomposite solutions were injected to a depth of -0.3 m to -1.2 m using the INJECT technology.
We also reinforced the base (ground) of the concrete slab of the roadway to a depth of -6.0 m from the daytime surface. Injections of gelocomposite ensured the stability of the base and made further subsidence impossible.
Stage 4. Geodetic survey of the concrete surface level. This allowed us to fix the initial situation and monitor the effectiveness of the work performed.
The entire complex of works envisaged by the project was completed within 7 calendar days. The customer received a 10-year warranty for the work, namely the absence of subsidence of the foundation and the development of deformations.
