Structure settlements at the Atommash plant as a result of prolonged soil wetting

Conclusions

1. In the 14 years that have elapsed since the start of construction on the Atommash plant, deformation phenomena, which have not, however, lowered the strength of the structure in the production buildings, have developed as a result of nonobservance of waterproofing requirements at the site in areas where surface-water domes that had developed as a result of prolonged wetting of the stratum from above have been detected. The design solutions for these foundations have ensured reliable operation under a rising GWT. The absolute settlements, exceeding those permitted by the Construction Rules and Regulations, affect less than 1% of the total number of columns in the buildings at the Atommash plant, while the relative settlements are within allowable limits. Cracks have formed in some auxiliary buildings primarily because their superstructures were built disregarding possible nonuniform foundation settlements.

2. The causes of pile-foundation settlements that had exceeded the standard values with respect to absolute magnitude are not associated with their bearing capacity, but are the result of deformations of the underlying soil layers that are not prone to slump-type settlement and to the development of deformation phenomena. This hypothesis explains the development of additional deformations in the stratum due to the compression of soils beneath the surface-water dome.

3. The deformation phenomena that develop at the site of the Atommash plant as a result of the wetting of the soil stratum from above do not affect the foundation settlements induced by live loads, and should be accounted for in design as a possible displacement of the area. It is possible to eliminate the effect of probable relative settlements on a structure by taking structural measures and observing waterproofing measures.

4. Under conditions favorable to the development of the deformation phenomenon, it is recommended to predict possible compressive deformations in a portion of the stratum underlying the stratum prone to slump-type settlement within the limits of the layers with a relative compression of more than 3% under a pressure equal to the natural pressure in compression devices.

5. Studies directed toward the nature of the processes explaining the development of the deformation phenomenon must be continued.