Effects of freezing-thawing cycles on porosity and geometric configuration of an artificial soils in laboratory modeling

Abstract

Variation in physical properties of soil depends heavily on freezing process during seasonal changes. Seasonal changes in cold humid regions lead to increasing of soil transformation speed. In the late autumn, soil profile is saturated with water through fallout. During winter, soil solution freezing leads to soil volume increasing due to water transition into the ice. Soil solution freezes in larger pores and the moment water flow stops, water phase transition leads to smaller pores and capillary deformation. Intensity of pore and capillary depletion will define extent of density changes during freezing. Rapidly developing urbanization process requires expansion of urban greening and tree planting, which can be successfully done by sustainable artificial soil implementation for each region, according to its climate conditions and pedogenesis. In order to observe possible porosity and structure changes in artificial soils and change rate due to freeze-thaw phenomenon, we have performed an experiment with a use of artificial soil models and then we have applied X˗Ray computer microtomography method to analyse soil pore space and its composition. As a result, we have seen significant compaction and pore diameter differentiation, as well as geometrical configuration changes.