Thermal Insulation Properties and Simulation Analysis of Foam Concrete Regulated by Mechanical and Chemical Foaming

To address, mitigate, or prevent thermal environmental issues arising from the heat dissipation of high-temperature surrounding rocks in deep hot tunnels, a research proposal is put forward based on previous studies and the team's initial experiments. The proposal involves using mechanical and chemical foaming to enhance the thermal insulation properties of foamed concrete, and this will be tested through engineering verification. Different proportions of cementitious materials, latex powder, polypropylene fiber, and self-made composite foam materials were designed using an orthogonal approach for testing the macroperformance and microstructure of foamed concrete. The pore structure of foamed concrete was quantitatively analyzed by Image-Pro Plus 6.0 software, and a fitting expression was established between thermal conductivity and the number of pores (1-2 mm). Characteristics of heat transfer inside the foam concrete were simulated and analyzed using COMSOL software, and the transmission path of heat streamline was found to be ″concave-convex form″, illustrating the blocking effect of foam concrete on heat. A thermal insulation engineering model was created using Fluent software to investigate the effects of thermal insulation layer thickness, water gushing heat release, seasonal factors, and other working conditions on the airflow temperature in the roadway before and after the application of foam concrete. The simulation results demonstrate that foam concrete can effectively reduce the airflow temperature in the roadway and weaken the surrounding rock heat dissipation. Additionally, it is found that the decreasing rate of heat dissipation of surrounding rock increases with the increase of insulation layer thickness, proving the engineering applicability of foam concrete for roadway insulation. The research results provide a theoretical basis and practical guidance for heat damage control of deep mining roadway.