Study on effect of temperature on diffusion characteristics of polymer slurry in a fracture
Self-expanding polymer grouting materials have been widely used in the rock reinforcement projects,but there is a lack of in-depth understanding of their grouting mechanism.Recent experimental studies have shown that temperature has a significant effect on the flow and diffusion process of self-expanding polymer slurry,because temperature changes alter the chemical reaction process of polymer slurry,which in turn affects its diffusion behavior.In order to deeply reveal the influence mechanism of temperature on the diffusion behavior of polymer slurry in cracks,a kind of self-expanding polyurethane polymer slurry applied in engineering is taken as the object.Based on the mechanism of slurry polymerization reaction and the theory of computational fluid dynamics,the quasi-three-dimensional finite-volume method is used to discretize the control equation of the flow of the slurry,and the three-dimensional finite-volume method is used to discretize the heat transfer equation of the crack wall.A coupled thermal-fluid system is established to simulate the expansion and diffusion process of the polymer slurry in the cracks.A coupled thermal-fluid simulation model is then established to simulate and analyze the expansion and diffusion process of the polymer slurry in the fissure,and the coupled solution of the chemical reaction process of the slurry,thus the flow field and the temperature field of the"slurry-fissure"system is realized.The model test of polymer grouting without horizontal plate fissure under different grouting volume and preheating temperature was carried out,and the applicability of the established numerical model was verified by comparing the measured data of slurry diffusion range,density and temperature with the calculation results.On this basis,the influence of preheating temperature and ambient temperature on the diffusion behavior of slurry in flat plate cracks was analyzed.The research results show that under the same ambient temperature conditions,with the increase of slurry preheating temperature,the slurry diffusion rate and heating speed accelerated,the peak temperature increased,and the moment of peak temperature point occurred earlier.Under the same preheating temperature conditions,the slurry diffusion rate and the diffusion radius increase with the ambient temperature.When the slurry preheating temperature or ambient temperature increases to a certain value,the final spreading range of the slurry will keep almost constant.When the ambient temperature decreases,the required minimum preheating temperature of the slurry gradually increases contrarily.The research results can provide reference for preheating temperature setting of polymer fracture grouting slurry.
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