Perminova O. Stress-strain State of Constructions of Two-layer Separate Foundations.

The object of study - constructions of two-layer separate foundations. The purpose of the study - to improve the efficiency of constructions of two-layer separate foundations. Research methods - experimental, using physical modeling techniques and the theory of rational planning, theoretical, based on mathematical processing of experimental data using least squares method. Theoretical and practical results - in order to improve the efficiency of constructions of two-layer separate foundations the necessity of experimental studies of the stress-stain state (SSS) of construction of two-layer separate foundations is justified by lack of methods for calculating the bearing capacity of constructions of two-layer separate foundations and reliable experimental data of the SSS of construction of two-layer separate foundations; performed experimental investigations of construction of two-layer separate foundations on the sandy grounds led to the qualitative and quantitative assessment of the impact parameter of two-layer structure on the strength, deformability and fracture of construction of two-layer separate foundations, as well as on the distribution of contact stresses in the subgrade; the analysis of experimental data and empirical relationships defined by the results of experimental studies found that increases the effectiveness of construction of two-layer separate foundations by increasing the carrying capacity, possibly through the use of flexible structures with a height of two-layer foundation layer of concrete of a higher class on the strength of not less than the height of the compressed zone and the contact with the transverse suture reinforcement; proposed method of calculation of construction of two-layer separate foundations, taking into account the peculiarities of construction of two-layer separate foundations under load as elements of the "subgrade - the foundation," with sufficient accuracy (3 ... 17%) approximate the results of theoretical calculations to experimental data, and therefore can be used in the design of construction of two-layer separate foundations of buildings and structures; proposed empirical correlations failure load of two-layer separate foundations from the design of foundations resulting from the processing of experimental test data of physical models of two-layer separate foundations on a sandy subgrade, can be used for planning of experimental studies of SSS of construction of two-layer separate foundations of natural size to improve the reliability of construction of two-layer separate foundations; improved construction of two-layer separate foundations under a column, protected by a patent of Ukraine for useful model; recommendations for the calculation and construction of two-layer separate foundations as elements of the "subgrade - the foundation" adopted CE "Alliance" to put into practice the design of building foundations and structures of gas stations. Novelty - the first time the features of SSS of construction of two-layer separate foundations are considered; the regularities of SSS of construction of two-layer separate foundations are considered on which the methodology for calculating the central and eccentrically loaded construction of two-layer separate foundations are proposed; proposed an empirical failure load depending on the parameters of construction of two-layer separate foundations are considered: the eccentricity of the application of an external load, the contact surface between layers of different classes of concrete of compressive strength, stiffness and relative height of the layer of concrete of a higher class of compressive strength. The degree of implementation - recommendations for the calculation and construction of construction of two-layer separate foundations as elements of the "subgrade - the foundation" adopted CE "Alliance" to put into practice the design of building foundations and structures of gas stations. Sphere (sector) application - construction.