Thawing of rocks in shaft sinking with artificial ground freezing

2021 ◽  
pp. 51-69
Author(s):  
O.S. Parshakov ◽  
L.Yu. Levin ◽  
M.A. Semin
Keyword(s):  
Ground Freezing ◽  
Shaft Sinking ◽  
Artificial Ground Freezing

scholarly journals Numerical simulation of vertical shaft sinking using artificial ground freezing

2021 ◽  
Vol 266 ◽  
pp. 03008
Author(s):  
M.S. Zhelnin ◽  
A.A. Kostina ◽  
O.A. Plekhov ◽  
L.Y. Levin
Keyword(s):  
Numerical Simulation ◽  
Soil Freezing ◽  
Design Parameters ◽  
Freezing Process ◽  
Vertical Shaft ◽  
Ground Freezing ◽  
Shaft Sinking ◽  
Artificial Ground Freezing ◽  
Ice Content ◽  
Fully Coupled

Artificial ground freezing (AGF) is used worldwide for vertical shaft sinking in difficult hydrogeological conditions. The modern tendency is to determine the design parameters of the freezing technique based on numerical simulation. This work is devoted to the numerical simulation of the formation of an ice-soil wall in the soil stratum due to the AGF and shaft sinking under the protection of the wall. For this purpose, a fully coupled thermo-hydro-mechanical model of soil freezing has been developed on the basis of the theory of poromechanics. The developed model considers important features of the freezing process, such as the phase change, pore water migration due to cryogenic suction, frost heave, and consolidation of the soil. The results have shown that the model allows to predict the distribution of ice content, assess stress and strain in the ice-soil wall, and estimate displacement of the excavation wall.

Effect of Freeze Pipe Eccentricity in Artificial Ground Freezing Applications

2020 ◽  
Author(s):  
Ahmad F. Zueter ◽  
Minghan Xu ◽  
Mahmoud A. Alzoubi ◽  
Agus P. Sasmito
Keyword(s):  
Energy Consumption ◽  
Radiation Heat Transfer ◽  
Conservation Equation ◽  
Underground Mines ◽  
Phase Front ◽  
Two Phase ◽  
Ground Freezing ◽  
Deep Underground ◽  
Artificial Ground Freezing ◽  
Conjugate Model

Abstract Building concentric tubes is one of biggest practical challenges in the construction of freeze-pipes of artificial ground freezing (AGF) applications for deep underground mines. In this study, the influence of tubes eccentricity on phase-front expansion (i.e., expansion of the frozen body) and energy consumption of AGF systems is analyzed. A 1+1D semi-conjugate model that solves two-phase transient energy conservation equation is derived. The model is firstly validated against experimental data and then verified with a fully-conjugate model from the literature. After that, the model is extended to a field scale of typical deep underground mines to study freeze-pipe eccentricity. The results show that an eccentric freeze pipe can reduce the phase-front expansion by around 25%, as compared with a concentric one. Also, the geometrical profile of the phase-front is significantly influenced by the freeze-pipe eccentricity. Furthermore, in the passive zone, where AGF coolants are isolated from the ground to reduce energy consumption, freeze pipe eccentricity can increase the coolant heat gain by 10%. This percentage can increase up to 200% if radiation heat transfer is minimized.

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