Consolidation of port paving. Port of Loano shipyard

The Port of Loano is one of the most important tourist ports in Liguria and one of the largest on the Riviera di Ponente. The basin contains a shipyard used for boat maintenance.

THE PROBLEM

The soil underlying the shipyard paving is loosely packed in some places, with a relative density (RD) of 25–51% depending on the sounding position and depth. It is constantly submerged below about 1.50 m below the floor of the service area. In addition:

concrete pavement thickness between 305 and 560 mm (average 374.70 mm);
insignificant paving reinforcement;
void under the slab between 5 and 55 mm (average 18.40 mm).

Customer needs
It was necessary to fill in the voids while compacting the ground below the slab to allow a new travel lift with a maximum capacity of about 900 tonnes to move safely.

Why the City of Venice chose Uretek:

Speed
careful planning and programming of the times allowed the work to be completed in a relatively short time;
Non-invasive
The intervention proposed by Uretek did not dirty the area or produce waste;
Localized work
The Uretek team delimited the work area, allowing regular port activities to continue;
Continuous monitoring of the work
Both during and after the intervention, the activities were subject to control by highly qualified personnel using advanced technology;
Exclusive Uretek technology
The intervention involved the injection of Uretek Geoplus® resin. With its high swelling pressure, it compacts the soil and stabilizes structures;
Respect for the environment
Above-ground mixing of the Uretek® resin creates a final inert product that does not release solvents into the soil or possible water tables in the area.

THE SOLUTION

We used our exclusive Uretek Floor Lift® technology to thicken the deep subgrade of the quay paving by injecting polyurethane resins with a high swelling pressure.
As the Uretek Geoplus® resin expands, it filled the voids in the soil, compacting the surrounding solid volume and improving its mechanical and hydraulic properties. We performed geotechnical verification and testing both during the work and upon completion. We stabilized 8142 sq. m of paving in 30 days without the need for accessory work or demolition.

THE INTERVENTION IN DETAIL

We injected the expanding resin with a maximum spacing of 1.50 m x 1.50 m on a square grid, starting at a depth of 1.20 m below the floor (-2.20 m in the area facing the dock), and working up to the intrados of the paving itself. We chose the ‘column’ type of injection, in which the injection tube is extracted from the ground at a controlled speed as the mixture is dispensed. We installed a temporary mobile work site, which occupied a suitably fenced-in portion of the paving each working day. 

The customer wanted to resume normal activities in the area the day after the injections were made. The operations involved an area of port paving equal to 8142.0 m², reaching a depth of 3.00 m below the paving in the dock area and a depth of 2.00 m below the paving in the shipyard area. We performed geotechnical verification and testing both during the work and upon completion.

Summary 

Consolidated the subgrade of 8142 m² of port paving.
Average paving thickness: 374.70 mm.
Average void below pavement: 18.4 mm.
Permissible design deformations depending on load conditions: 5–9 mm.
Deformations detected in the same load condition during testing: 0.5–3 mm.
Intervention performed in 30 working days with a productivity of about 270 m²/day.