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Acrylic materials exhibit favorable grouting repair performance. However, their curing products are easily inclined to drying shrinkage, and their concrete impermeability repair characteristics have seldom been investigated. To improve material properties, reveal the impermeability repair mechanism, and address drying shrinkage, this study proposed the addition of styrene–acrylate copolymer emulsion (styrene–acrylic emulsion) to the grouting material to prepare two-component acrylate grouting materials. Using orthogonal and single-factor tests combined with physical and mechanical properties, the mechanical properties and impermeability repair performance (physical and mechanical properties combined) of grouting materials were analyzed and studied, and the optimal ratio of each component of acrylate grouting materials was determined. Results show that (1) the hydrogel produced by the reaction of sodium methacrylate with hydroxyethyl acrylate has good physical and mechanical properties. (2) With the increase in the accelerator dosage, the setting time of slurry initially decreases and then increases; as the initiator dosage increases, the setting time of slurry decreases, which is negatively correlated with the initiator dosage. (3) Talcum powder can improve the physical and chemical properties of gel and enhance the reliability and durability of acrylate grouting materials, and the comprehensive performance is the best at a dosage of 3%. (4) Styrene–acrylic emulsion can increase the solid content and reduce the volume drying shrinkage when added to grouting materials. The fractured impermeable specimens were repaired by grouting with prepared acrylate grouting materials and cured for 24 h for the impermeability test, and the water pressure for the 24 h impermeability repair was 1.0 MPa. This study’s results provide important reference and basis for revealing the impermeability principle of acrylate grouting materials and evaluating their impermeability.

The breakdown process of high-voltage pulse discharge under water involves rapid changes in the plasma channel, which are influenced by various factors, such as time, electric field, and thermal field. Accurately measuring the plasma channel is challenging due to technological limitations. This study proposed the theory of equivalence and equivalent numerical simulation for underwater pulsed discharge to understand the breakdown process and the role of the plasma channel in high-voltage pulse discharge under water. It established the equivalence theory and numerical simulation of the discharge breakdown process by considering the delay characteristics of discharge breakdown and the plasma channel model. The plasma channel was described intuitively and quantitatively, providing a concise and effective analysis of the complex breakdown process. Results indicate that (1) the breakdown channel undergoes an initial plasma channel stage accompanied by heating effects, which then transforms into an arc channel, leading to breakdown and detonation. (2) The equivalent resistance of the plasma channel is approximately 10 Ω, and the equivalent radius of the initial channel is around 0.1 μm. Breakdown is difficult to achieve when the electrode spacing is 0.5 cm and the charging voltage Um is below 5.5 kV, with an estimated minimum charging voltage of approximately 6 kV required for breakdown. (3) Equivalence theory enables effective quantification of the equivalent radius and equivalent resistance in the breakdown process, providing a representative measure of breakdown process stability. It proves to be an effective method for monitoring the operation of discharge equipment in practical engineering. The study provides a reliable reference for assessing the breakdown process of underwater high-voltage pulse discharge and monitoring the performance of pulse discharge equipment. [ABSTRACT FROM AUTHOR]