Experimental Research on the Performance Characteristics of Grouting Slurry in a High-Ground-Temperature Environment

Grouting materials with good thermal insulation and reinforcement properties are the key factors in solving the temperature control problems of high geothermal tunnels using curtain grouting, as the existing grouting materials are unable to take into account the working performance and thermal insulation properties of high-temperature environments. In view of the above problems, this paper configures a high geothermal tunnel red-mud-based grouting material (RMGS) using red mud, carries out tests on the working performance (viscosity, setting time, and compressive strength) and thermal insulation performance (thermal conductivity and specific heat capacity) of the grouting materials at different temperatures (20, 40, 60, and 80 °C), and analyses the variation rules and micro-mechanisms of the various properties at different temperatures. The results show that the increase in temperature will accelerate the viscosity development and condensation of the grouting material and will also lead to the acceleration of the attenuation of the thermal conductivity of the three types of grouting material and the reduction in specific heat capacity. In addition, the appropriate temperature can improve the compressive strength of the material. The increase in temperature will accelerate the hydration reaction speed of the grouting material and will also lead to the development of the internal pore space of the material, which affects the macroscopic properties of the material and is the reason for the effect of the temperature on the performance of the grouting material. In terms of application, the cement slurry is suitable for grouting in a static water environment, the cement–water glass bi-liquid slurry is suitable for grouting in a dynamic water environment, and the RMGS is suitable for grouting in a high-ground-temperature environment.

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