RESEARCH OF METRO TUNNEL SEDIMENTS UNDER THE CONDITIONS OF A WATER-SATURATED FLOOD MASSIVE

Purpose: analysis and selection of an appropriate way to improve the strength characteristics of soils by strengthening in the zones of weakening and reducing deformations of the tunnel structures, substantiating the methods of strengthening the base of the subway tunnel structure and the soil massif during deposition in the conditions of the underground space. On the basis of the analysis, propose an expedient method and schematic fixing of a water-saturated non-washable soil massif with stabilization of sediments and propose a method for reducing deformations during vibration subsidence. 
Methodology: by using the survey and analysis of methods of strengthening the soil massif, geophysical methods of strengthening the foundations of the sandy water-saturated massif, a comprehensive approach is recommended for the implementation of increasing the level of strength of the subway tunnel. 
Originality: on the basis of the performed analytical studies, the parameters for strengthening the soil of the water-saturated alluvial massif were determined and the combined method of strengthening the soil massif and the method of reducing the vibration subsidence caused by the speed of the trains in relation to the force of gravity during the oscillation of the structure of the base of the subway tunnel in the water-saturated alluvial massif were proposed. optimization of works, reduction of work terms and the possibility of applying a combined scheme of filling wells with solution and using them in conditions of dense urban development. 
Findings and practical implications:  the combined scheme of strengthening the soil massif with the help of gas silicification and the installation of soil-polymer piles will allow to evenly reduce the sedimentation of the soil and the structure without harming the surrounding underground space and dense urban development, in particular, it will increase the strength characteristics and the service life of the distillation tunnel. 
Keywords: physical and mechanical properties; water-saturated alluvial massif; subway tunnels; shallow laying; geophysical methods; tunnel deposition; tunnel fastening, gas silicification; low viscosity polyurethane.