The paper studies the influence of the geometric parameters of the mixer on the mixing process, the construction of the mixing body, its location in the mixer bulk, and the mixer shape and geometry. The technique of calculating the power spent on mixing the foam concrete mixture is described. The effects of the ratio of the mixture height to the mixer diameter, the number and width of reflective partitions, and the shape of the conical part of the mixer on the homogeneity of the foam concrete mixture and the power consumption are considered. The optimal ratios of the foam concrete mixture height to the mixer diameter have been determined. Moreover, the optimal range of the ratios of the partition width to the mixer diameter has been established, in order to obtain a homogeneous foam concrete mixture throughout the volume with lower energy consumption. The optimal values of the angle of the mixer conical part for the preparation of a foam concrete mixture have been determined.

Subsiding soils are structurally unstable and are common and Russia (Northern Caucasus, Western Siberia, etc.) as well as worldwide (China, Mongolia, Central Asia, North America, etc.). Construction and operation of buildings and structures on such soils are associated with the nonuniform subsiding of soil due to water saturation, which causes excessive deformations in basements and foundations. The geotechnical and technogenic conditions of Eastern Donbass feature the commonness of subsiding loess soils and undermining of industrial areas prone to waterlogging. The three mentioned factors have a negative impact on ground facilities due to nonuniform vertical and horizontal deformations of the Earth’s surface. Despite considerable scientific progress in studying the surficial deformations attributable to various factors, the concurrent effects of undermining, technogenic waterlogging, and manifestation of subsiding properties on the condition of buildings and structures are currently understudied. This paper proposes a method for predicting the deformation of subsiding massifs in the undermined areas of Eastern Donbass. The research team has developed an analytical method for assessing the damage to a typical urban structure simultaneously exposed to soil subsidence and undermining.

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An analysis of turbulent transport patterns in mixers revealed specific features of the flow hydrodynamics of the mixed medium with regard to mixers either without internal devices or with internal devices of small cross-section. Despite the increasing popularity of mixers without internal devices, experimental studies were carried out mainly in mixers with baffles, since they provide a higher turbulence of the mixing process allowing effective preparation of foam concrete mixtures with evenly distributed components throughout the mixer volume. Experimental studies of the dependence of peripheral velocity on the characteristics of the internal devices of the mixer in the preparation of foam concrete mixtures showed a high degree of agreement between the experimental and calculated data. Calculations based on the equations provided in the article and measurement results indicate that, when fixed elements are attached to the mixer, the circumferential velocity is significantly reduced. It should be noted that the fixed devices installed in a mixer are affected by hydrodynamic forces. The results of the conducted experiments and comparisons demonstrated that, when preparing a foam concrete mixture in a turbulent mixer without internal reflective baffles, the effect of a cylindrical surface with a turbulent diffusion ratio equal to zero makes it impossible to evenly distribute the mixture components throughout the volume and pore the mortar mixture.