The effect of cryogenic suction on the monitoring data of ice barrier formation in a porous water-saturated soil

Abstract

Artificial ice wall formation is one of the most frequently used techniques for waterproofing of mineshafts constructed in water-saturated rock massifs. In this work, we have developed a complex monitoring system for control of formation of ice. The system includes hydro-observation and temperature monitoring wells combined with simulation module. At the beginning of the monitoring process, we observed contradictory indications of ice wall closing moment by hydro-observation and temperature monitoring subsystems. To explain this effect we introduced in the simulation module two models of ground freezing, which consider the key effects observed under the phase transition in a saturated soil. There are existing of nonequilibrium moisture content in the soil at negative temperatures, kinetic peculiarities of water-ice transition in a porous medium and redistribution of moisture in partially saturated soil. Based on the detail simulation model we have shown that moisture content inside the closed ice wall can decrease due to water migration towards the phase transition front, which, consequently, slows down the water level in hydro-observation wells.