Granulated foam-glass ceramics for ground protection against freezing
The problem of seasonal freezing and frost heaving of soils of the engineering structures foundations is considered. For the purpose of thermal protection of soils, a granular inorganic closedporous material, named granulated foam-glass ceramic is proposed. In the laboratory modeling of seasonal freezing, the dynamics of temperature and deformation, as well as the distribution of moisture over the depth of the soil, were studied in three cases: a soil without thermal insulation, a soil with a layer of granulated foam glass ceramics and a soil with an extruded polystyrene layer. Simulation was carried out with ensuring the flow of water to the freezing front. Heat-insulating layers allow to reduce frost heaving of models to the same extent (in comparison with soil without insulation) due to the decreasing of the depth of soil freezing. As a result, the relationship of soil deformations with the distribution of temperature and humidity over the depth of the soil was established. The increased frost heaving deformation of the soil without a heat-insulating layer is explained by the significant migration of capillary water to the upper layer of soil at freezing. The data of the annual monitoring of the experimental road section with the thermal insulation layer of granular foam-glass ceramics placed in embankment is given. The suggested constructive measure was made it possible to substantially reduce the depth of seasonal freezing of the soil compared with the typical road section.