During the operation of a warehouse complex, emergency wetting and partial washout of soil occurred in the foundation of the floor structures, leading to a change in the deformation modulus of the foundation and damage in certain areas.

Task
Determine the degree of loosening of the foundation, delineate the areas of soil washout in the foundation of the floor structures, and ensure normal operating conditions of the facility, namely:

• eliminate floor slab settlement within 50 mm,
• level the diagonals of the floor slab sections,
• eliminate the resulting tilt of the racking,
• ensure normal operation of door units in problem areas.

Normal operation: operation of a construction facility in accordance with the conditions provided for in building codes or the design brief, including appropriate maintenance, major repairs and reconstruction GOST 27751-2014, article 2.1.7

First of all, URETEK specialists performed a visual inspection of the facility and determined a list of further actions.
To determine the mechanical properties of the foundation soil, assess the uniformity of its structure, and identify and delineate loosened zones, dynamic probing of the foundation soil was carried out from the clean floor surface of the premises at 22 points of suspected soil loosening.
To determine the volume of voids formed under the floor slab structure, an inspection of the sub‑slab space was performed at 34 points using a video scope.
Data on slab irregularities were obtained by geodetic surveying and recorded in a report on the work performed.
After office processing of the results, a technical solution was developed that included:

• deep strengthening of the foundation soils under 130 m² of the floor slab structure using the Deep Injection method;
• filling 2.46 m³ of voids in the foundation under the floor slab structure using the Slab Lifting method;
• lifting and levelling 130 m² of floor slab to a horizontal plane, together with eliminating the resulting racking tilt, using the Slab Lifting method. The average lift of the floor slab structure in the work area was +42 mm.

All work was carried out inside an operating facility, with minor (not affecting business processes) restrictions on the use of certain zones.
The use of the URETEK injection method improved the construction properties of the soils and, in a minimum time, eliminated the resulting tilt of the racking structures and returned the facility to a state suitable for normal operation without stopping its functioning or unloading the racking structures.