Justification of the application of low-viscus polyurethane in conditions of poorly water-saturated soils

Abstract

Purpose. Analytical justification of the method of strengthening the stability of the water-saturated alluvial soil massif around the subway tunnel by the method of jet cementation using low-viscosity polyurethane. Consider the advantages of this material and present the strength characteristics. The methods. Analytical justification of the method of strengthening the stability of the water-saturated alluvial soil massif around the subway tunnel by the method of jet cementation using low-viscosity polyurethane. Consider the advantages of this material and present the strength characteristics. Findings. The use of a mixture of concrete and low-viscosity polyurethane during jet cementing allows to increase the strength characteristics of piles, thanks to the advantages of polyurethane. The material has a high density, ozone resistance, stability at high and low temperatures, the possibility of use under significant mechanical loads, with a high density, it does not have a large mass, it is elastic. When filling wells with a mixture of cement and polyurethane solution in interaction with water-saturated soil, the physical and mechanical characteristics of the soil and the load on the structure of the metro tunnel change. Based on the analysis of the data on the consolidation of the soil massif, it can be highlighted that to increase the stability of the water-saturated soil massif, it is advisable to use the jet cementation method with the addition of low-viscosity polyurethane. The originality. The use of low-viscosity polyurethane as a cementing material by jet cementation is highly effective in cementing weak water-saturated soils. The use of polyurethane will make it possible to shorten the period of work, reduce the amount of material, and increase operational characteristics. Practical implementation. The silicification method is common and convenient for strengthening underground soil in the case of dense urban development, but the use of piles as a result of mixing soil with polyurethane will not only reduce the duration of work, but also reduce the cost and increase the speed of pile hardening, increase the range of coverage of the water-saturated massif near the tunnel, will reduce the possibility of the formation of an anti-filtration cushion, which is safer for urban development