To enrich the acidizing fracturing fluid system,formic acid and hydrofluoric acid are used as representatives for corrosion treatment of coal samples to explore the mechanical damage laws of organic and inorganic acids on coal samples.Uniaxial compression experiments are used to explain the transformation mechanism of acid liquor on the mechanical properties of coal bodies.The results show that hydrofluoric acid has a significant effect on reducing the compressive strength of raw coal compared to formic acid.The peak stress of the 15%concentration hydrofluoric acid coal sample is 54.28%lower than that of raw coal,and the total energy required for instability and failure is 73.73%lower than that of raw coal.The comprehensive transformation effect of compressive strength is the best.Formic acid has a significant effect on improving the toughness of coal compared to hydrofluoric acid.The peak strain of 15%concentration formic acid coal sample is only reduced by 18.80%compared to raw coal.The total energy input rate is relatively slow and the value is relatively high,and the comprehensive toughness transformation effect is the best.
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