Multi-loop pipe freezing optimization of deep shaft considering seepage effect

Abstract The delay of the closure of frozen wall occurs frequently due to the excessive groundwater seepage in the construction of deep shaft using artificial freezing technology. The same problem also appears in the freezing construction of new westerly shaft in Pansan Coal Mine of Huainan, whose l...
Ausführliche Beschreibung

Abstract The delay of the closure of frozen wall occurs frequently due to the excessive groundwater seepage in the construction of deep shaft using artificial freezing technology. The same problem also appears in the freezing construction of new westerly shaft in Pansan Coal Mine of Huainan, whose located stratum suffers from the groundwater seepage of 7.96 m/d. Obviously, the original three-loop pipe freezing scheme under the static water condition is not applicable; it must be optimized to meet the construction requirements. Therefore, the evolution law of temperature field of deep shaft freezing wall under different groundwater seepage velocities was studied based on the coupled equations of temperature and seepage field using COMSOL Multiphysics finite element program. Finally, the optimal freezing scheme of new westerly shaft was proposed and applied to practical engineering. Compared with the original freezing scheme, the optimized freezing scheme shortened the closure time of freezing wall and increased the effective thickness of freezing wall, which ensured the safety of deep shaft construction and produced good social benefit. Ausführliche Beschreibung