Construction on loess soils

Conclusions 1. Inadmissible settlements and tilts of several multistory buildings in Volgodonsk are the result of collapse of the soils under external loads owing to disregard of the requirements for elimination of the collapsibility within the limits of the entire deformable zone under shallow foundations.2. The cause of the possible settlements of structures on pile foundations fully cutting through the collapsible mass lies in development, under soaking from the top, of deformation phenomena with compaction not only of the collapsible layers but also of the underlying non-collapsible soils, which was first mentioned in 9].The concept that the most hazardous situation for a pile foundation, in this regard, occurs when collapse takes place under the weight of the overlying mass with the GWL rising from bottom to top is erroneous and is not confirmed by construction experience.3. In the development of deformation phenomena, it is important to distinguish between the active period and the settlement attenuation period, since differential settlements occur only during the active period for all practical purposes.4. It is possible to eliminate completely the possibility of substantial settlements of structures under severe Type II collapsibility conditions either by construction of deep founations carried to 40–50 m so that they will rest on solid material, or by elimination of the possibility of soaking of the soils. These highly uneconomical solutions can be used only in especially important cases. On the other hand, in the massive construction practice it is justifiable to correctly fulfill the SNiP requirements, taking into account the possible additional settlements caused by compression of the underlying noncollapsible soils.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 24–27, January–February, 1991.