The challenge of precisely controlling crack propagation induced by high-voltage electric pulses is important in the field of rock mass engineering. This study uses a combined experimental–theoretical–simulation approach to systematically investigate how the regulatory mechanisms of hole diameter and spacing parameters affect the electrohydraulic fracturing of sandstone. A high-voltage electric pulse test system integrated with ultradynamic strain monitoring and microcrack characterization techniques is employed, and a fluid–solid coupling numerical model is constructed on the basis of the principle of energy equivalence, revealing the directional control mechanisms of hole structures at multiple scales, including apparent crack distribution characteristics, dynamic strain response features, internal damage evolution, and energy distribution patterns. The results indicate that the diameter of the empty hole significantly affects the complexity of the crack network. Larger diameter holes increase the number of secondary cracks and increase the fractal dimension to 1.4213 but decrease the length of the primary crack. A small spacing controls the crack deviation angle within 5° through stress wave interference. The combination of larger diameter holes and a small spacing increases the peak surface strain to 23.51 × 10–4, increases the load duration to 0.400 ms, and increases the final deformation to 0.366 mm. The peak pressure on the hole wall is positively correlated with the diameter of the empty hole, reaching a maximum of 2.098 kN, which is a 471% increase compared with that in the scenario without empty holes. As the hole spacing increases, the pressure field rapidly decreases. A 22 mm diameter combined with a 40 mm spacing optimally balances the directional accuracy and energy utilization efficiency. This study quantitatively reveals the synergistic regulatory mechanism of the “diameter‒spacing” parameters of air holes during liquid-electric fracturing, providing a theoretical basis for parameter selection in engineering practice: 1 times the aperture plus 2 times the spacing is suitable for high-precision fracturing, whereas 1.5 times the aperture plus 3 times the spacing is suitable for dense fragmentation.Highlights<UnorderedList Mark="Bullet"> <ItemContent> A quantitative model between the diameter–spacing parameters of empty holes and the fractal characteristics of cracks is established, revealing the directional control mechanism of crack propagation in rock breaking by electrohydraulic effects. </ItemContent> <ItemContent> A multidimensional dynamic strain fitting model between the diameter–spacing parameters of empty holes and the peak strain, time parameters, and deformation amount is constructed to elucidate the regulatory effect of empty holes on stress waves. </ItemContent> <ItemContent> On the basis of the principle of energy equivalence, a fluid–solid coupled numerical model for electrohydraulic rock breaking is developed to elucidate the internal damage evolution and energy conversion mechanisms during electrohydraulic impact. </ItemContent> </UnorderedList>

Study on the Influence Mechanism of the Void Structure on the Directional Propagation of Cracks Induced by High-Voltage Electric Pulses

期刊论文
发表日期：

2026年2月2日

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Jun Guo,
Quan Liu,
Guorui Feng,
Jinwen Bai,
Zilong Zhang,
Xiaoze Wen,
Linjun Zhu,
Rongwang Qin,
Dias Daniel

摘要

The challenge of precisely controlling crack propagation induced by high-voltage electric pulses is important in the field of rock mass engineering. This study uses a combined experimental–theoretical–simulation approach to systematically investigate how the regulatory mechanisms of hole diameter and spacing parameters affect the electrohydraulic fracturing of sandstone. A high-voltage electric pulse test system integrated with ultradynamic strain monitoring and microcrack characterization techniques is employed, and a fluid–solid coupling numerical model is constructed on the basis of the principle of energy equivalence, revealing the directional control mechanisms of hole structures at multiple scales, including apparent crack distribution characteristics, dynamic strain response features, internal damage evolution, and energy distribution patterns. The results indicate that the diameter of the empty hole significantly affects the complexity of the crack network. Larger diameter holes increase the number of secondary cracks and increase the fractal dimension to 1.4213 but decrease the length of the primary crack. A small spacing controls the crack deviation angle within 5° through stress wave interference. The combination of larger diameter holes and a small spacing increases the peak surface strain to 23.51 × 10^–4, increases the load duration to 0.400 ms, and increases the final deformation to 0.366 mm. The peak pressure on the hole wall is positively correlated with the diameter of the empty hole, reaching a maximum of 2.098 kN, which is a 471% increase compared with that in the scenario without empty holes. As the hole spacing increases, the pressure field rapidly decreases. A 22 mm diameter combined with a 40 mm spacing optimally balances the directional accuracy and energy utilization efficiency. This study quantitatively reveals the synergistic regulatory mechanism of the “diameter‒spacing” parameters of air holes during liquid-electric fracturing, providing a theoretical basis for parameter selection in engineering practice: 1 times the aperture plus 2 times the spacing is suitable for high-precision fracturing, whereas 1.5 times the aperture plus 3 times the spacing is suitable for dense fragmentation.

Highlights

A quantitative model between the diameter–spacing parameters of empty holes and the fractal characteristics of cracks is established, revealing the directional control mechanism of crack propagation in rock breaking by electrohydraulic effects.

A multidimensional dynamic strain fitting model between the diameter–spacing parameters of empty holes and the peak strain, time parameters, and deformation amount is constructed to elucidate the regulatory effect of empty holes on stress waves.

On the basis of the principle of energy equivalence, a fluid–solid coupled numerical model for electrohydraulic rock breaking is developed to elucidate the internal damage evolution and energy conversion mechanisms during electrohydraulic impact.