Physical Simulation Test on Temperature Field Distribution of Artificial Vertical Straight Multirow Freezing Inclined Shaft

Abstract

This study investigated the temperature field distribution of a freezing inclined shaft. Thus, a three-dimensional physical simulation test system was developed, and the system consists of six parts, which are simulation box and shaft model, loading system, freezing system, external environment simulation system, and data acquisition system. From the results of physical and mechanical property test of artificially frozen sand, in the range of 25°C to -20°C, the heat capacity of sand decreases first, then increases, decreases, and finally tends to be stable; the thermal conductivity of sand gradually increases and finally becomes stable; and the cohesion, internal friction angle, uniaxial compressive strength, and elastic modulus of artificially frozen sand all increase as the freezing temperature decreases. The three-dimensional physical simulation test and field measurement showed that the distance from the freezing pipe is the main factor affecting freezing wall temperature, and the closer to the freezing pipe, the faster the cooling rates. Comparison of theoretical calculation results and field measurement results shows that the calculation formula of freezing wall temperature with time of the inclined shaft can reflect the general law of freezing wall temperature cooling. Therefore, the 3D physical simulation test system is reliable and the test method is feasible.

Study on Temperature Field Evolution and Frozen Wall Closure Judgment Criteria of Inclined Shaft under Inclined Holes Freezing Condition

“…Their simulation results are coherent with the experimental results [14]. At present, the studies on the temperature field of freezing method mainly focus on vertical shaft, and the used methods are mainly based on numerical simulation, which lacks physical experiments to reveal the actual freezing situation [15].…”

“…They deduce that the heat capacity of sand first decreases, and then increases. Afterwards, it decreases and finally tends to be stable during cooling in the range of 25 °C to -20 °C [15]. He and Du et al (2017) conduct an analysis for the development of temperature field and frozen wall in water rich silty stratum, based on the field detection and numerical simulation.…”

“…The current study mainly focuses on the vertical freezing hole. In addition, there is a lack of understanding of temperature field for the inclined freezing hole method, which is the main limitation of the development of this method [15]. Fan (2014) compares the formation characteristics of the freezing curtain when the inclined shaft is frozen along the axis with the vertical freezing method.…”

Temporal and Spatial Evolution Laws of Freezing Temperature Field in the Inclined Shaft of Water-Rich Sand Layers

“…They investigated the thermal change law of the frozen wall and the mechanical properties of the shaft wall during the defrosting process. Sun et al [14,15] combined physical and mechanical tests, field measurements, and finite element numerical simulations to analyze the mechanical properties and temperature-field evolution of inclined-shaft frozen walls when traversing water-rich sand layers. Chen et al [16] established a large-scale three-dimensional freezing model test bench and studied the temperature field distribution law of the frozen wall of the inclined shaft under the two freezing methods of vertical hole and inclined hole.…”