考虑水盐含量的土体雷电冲击响应多场耦合数值模拟研究

Multi-Field Coupled Numerical Simulation of Lightning Impact Response of Soil Considering Water and Salt Content

摘要: 雷击产生的强大电流会使土体击穿，在含水量和含盐量较高的土体中，这种效应尤为显著。文章针对土体在不同含水量和含盐量下的雷电冲击响应特性开展研究。结合COMSOL Multiphysics软件建立土体雷电冲击数值模型，并开展室内试验对数值模型的有效性进行验证，在此基础上对不同含水量和含盐量的土体雷电冲击规律进行分析。结果表明，土体冲击电压峰值会随着含水量与含盐量的增加而增大，在相同含水量条件下，含盐量的增加进一步提高了冲击电压峰值。然而，当含水量或含盐量达到一定饱和状态后，冲击电压的变化趋于平缓。此外，含水量和含盐量对电场强度也具有直接影响，较高的含水量和含盐量不仅增加了土体的电场强度，还扩大了其影响范围。热效应分析表明，在本研究的参数条件下，较高含水量(20%)土体温度传导影响范围达0.12 m，而低含水量(5%)时热效应范围缩小至0.09 m，含盐量的变化对热效应影响较弱。含水量和含盐量的变化对土体响应特性有显著影响，本研究为雷电防护工程的设计提供了重要的理论支持，具有显著的工程应用价值。

Abstract: Soil breakdown can be induced by the intense current generated during lightning strikes, with this effect being particularly significant in soils with high water and salt content. This study examines the response characteristics of soil to lightning impulse under varying water and salt content conditions. A numerical model of soil lightning impulse was established using COMSOL Multiphysics software, and the model’s validity was verified through laboratory experiments. Based on the validated model, systematic analyses were performed on the patterns of lightning impulse in soils with different water and salt content. The results demonstrate that the peak impulse voltage in the soil is elevated by increased water and salt content. Under constant water content conditions, the peak impulse voltage was found to be further enhanced by increased salt content. However, the impulse voltage variation is observed to stabilize when certain saturation levels of water content or salt content are reached. Additionally, the electric field intensity is directly influenced by water and salt content, whereby the soil’s electric field intensity is not only enhanced, but its area of influence is also expanded by higher levels of these parameters. The analysis of thermal effect shows that the range of influence of temperature conduction of soil body reaches 0.12 m under the parameter conditions of this paper for higher water content (20%), while the range of thermal effect narrows to 0.09 m for low water content (5%), and the change of salt content has a weaker influence on the thermal effect. Soil response characteristics are significantly influenced by variations in water and salt content. This research provides essential theoretical support for lightning protection engineering design, and significant practical engineering value is demonstrated.