Research object - the process of interaction between soil base and water-cement-silica mixture pumped under high pressure, and consequent modification of soil base properties. Aim of the thesis - development of theoretical principles for strengthening of soil bases using the method of high pressure grouting and design of reinforced soil bases. Research methods: standard laboratory methods for determining the properties of the soil base before and after cementation; radioactive gamma-ray logging to determine the density, the method of cross-hall to determine the seismic stiffness of the array, the method of monitoring changes in natural electromagnetic field of the Earth, a visual method for the study of spatial structures after grouting, geophysical research methods, methods of monitoring the settlements of buildings and structures, methods of mathematical statistics, mathematical modeling techniques to determine the stress-strain state of the soil base. Theoretical and practical results: scientifically based and theoretically developed design methodology for strengthening of soil bases using cementation under high pressure, which allows reasonable use of the design process parameters depending on the characteristics of strength and deformation properties of the soil, soil base calculation with the account of strengthening. Scientific novelty: classification of soil bases high pressure grouting method has been performed, proposed physical model and mathematical formalization of the process of high pressure grouting of ground bases with description of the stress-strain state in the process of grouting execution using the theory of independent filtration consolidation, further asymptotic solution estimates and determination of the limit state areas based on spatial law of the limit equilibrium; theoretical foundations for grouting process , the basic pattern of injection execution process, namely the critical grouting pressure, dimension of the grouted soil bass, the critical depth of injector immersion, grouting duration, basis deformation, for the first time experiment presents features of grout distribution in soil base depending on the injection pressure, borehole diameter, injection depth, injection duration; newly suggested solutions for design of soil base strengthening and calculation of strengthened soil bases after cementation. Implementation scope: research results have been utilized in the development of DBN 2.1-10-2009 "Bases and foundations of structures" the governing document RD EO 0624-2005, implemented in the design and strengthening of foundations of 55 objects, including object " Shelter "Chornobyl NPP with economic benefit of 7.0 million UAH. Application scope: strengthening of foundations of buildings and structures above and below groundwater level, settlement and inclination stabilization, elimination of subsidence properties, fixing the walls of trenches, conservation of radioactive and common waste, cutoff curtains execution.
