Restoration work after washing the soil under the slab-pile foundation

Problem:

After a large-scale break in the water pipe, a large amount of water got under the floor slab and under the foundation. In particular, the ground around the piles was washed away, resulting in cracks along the walls of the house with an opening of up to 1-2 mm. The detected slab subsidence was in the range from 15 mm to 155 mm. After carrying out a set of works on the investigation of physical and mechanical characteristics of the soil, local voids with a capacity of up to 300 mm were found, as well as a serious decompaction of the soil in the range from 0 to 3 meters.

Task:

Return the base slab to the design level, as well as stabilize the foundation piles.

Decision:

To restore the working condition of the residential building, the foundation was reinforced under the foundation slab: the piles were stabilized by deep injection. After increasing the load-bearing capacity of the base, the Slab lifting method was used to lift and re-level the foundation slab to the design marks. All work on lifting and leveling the structure was under the constant supervision of the geodesic service.