Soil resistivity is the average value of soil resistance per unit length, measured in ohms meters.
The main influencing factors of soil resistivity:
1. The impact of soil quality
Different soil types have different soil resistivity.
2. The influence of temperature
When the temperature drops again, ρ Significantly increased; When the temperature starts to rise from 0 ° C, ρ It will only steadily decline.
3. The influence of conductive ion concentration and soil moisture content in soil
Soil resistivity ρ The size mainly depends on the concentration of conductive ions in the soil and the water content in the soil. The higher the concentration of conductive ions in soil, the better its conductivity, ρ The smaller;
4. The effect of soil compaction
The density of soil can have a certain impact on soil resistivity. When the moisture content of clay is 10%, the temperature remains unchanged, and the unit pressure increases from 1961 Pa to 19610 Pa, an increase of 10 times, ρ Can be reduced to 65% of the original.
Therefore, in order to reduce the flow resistance of the grounding electrode, it is necessary to compact the backfill soil around the grounding body, so that the grounding electrode is in close contact with the soil, thereby reducing the soil resistivity.
5. The influence of seasonal factors
Seasonal changes can cause changes in soil resistivity, with rainfall and freezing being the most significant factors affecting soil resistivity.
During the rainy season, due to the infiltration of rainwater, the surface soil ρ Reduce, lower than deep soil; In winter, due to the freezing effect of soil, the surface soil ρ Increase, higher than deep soil.