Analysis of the structural integrity of a frozen wall during a mine shaft excavation using temperature monitoring data

Abstract

This paper describes the results of the temperature monitoring of a frozen wall (FW) around the skip shaft of a potash mine under construction. The data on temperature measurements in control-thermal boreholes were used to parameterize the mathematical model of heat transfer, which allowed for the reconstruction of the temperature field throughout the entire cooled and frozen soil volume. The resulting temperature distribution in the FW zone for greater than 1 year was used to determine the distribution of the strength properties and calculate the temporary change in the limiting value of the external lateral load on an FW of a given thickness and specified thermomechanical properties. The obtained dependencies of the maximum external load on the FW can be used to optimize the operation mode of the freezing station at the ice holding stage (or passive freezing) to increase the energy efficiency of the system and ensure the structural integrity of the FW.

Influence of soil salinity on the bearing capacity of the frozen wall

“…Dependencies ( 1)-( 2) enable the approximate estimation of the decrease in the bearing capacity of the FW in the presence of dissolved salt in frozen soil layers. If we assess the load-bearing capacity of an FW in terms of the maximum load P on the side wall of the FW [26], then the limiting state of the FW can be expressed by a criterion dependence of the form:…”