Research on the Explosion Effects and Fracturing Mechanism of Liquid Carbon Dioxide Blasting

Recently, liquid carbon dioxide (L-CO2) blasting technology has again attracted increasing attention due to its good fracturing effect and safety performance, especially in the research field of coal seam permeability improvement. However, the fracturing mechanism has not been explained. In this paper, the blasting effect of L-CO2 blasting technology was analyzed based on L-CO2 blasting experiments, and the fracturing mechanism of L-CO2 blasting technology was studied from the perspective of stress wave action via theoretical analysis and peridynamic simulations. The research results indicate that (1) after L-CO2 blasting, there is no crush zone around the blasting hole, and only 3 ~ 5 cracks are observed, while the proportion of large fragments is large. (2) A lower loading rate and strength of the stress wave are the main reasons why L-CO2 blasting technology achieves a good fracturing effect. (3) With increasing loading rate of the stress wave, a crush zone is readily formed around the blasting hole, the number of cracks increases, and the radius of the fractured zone decreases under the action of the stress wave.