Soil resistivity is the average value of soil resistance per unit length in ohm-meters.
The main influencing factors of soil resistivity:
1. The influence of soil quality
Different soil types have different soil resistivity.
2. The influence of temperature
When the temperature drops again, ρ increases significantly; when the temperature rises from 0 degree , ρ only decreases steadily.
What is soil resistivity and what are its influencing factors
3. The effect of the concentration of conductive ions in the soil and the water content in the soil
The size of soil resistivity ρ 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 the soil, the better the conductivity of the soil, and the smaller the ρ;
4. The effect of soil compaction
The density of the soil will have a certain influence on the soil resistivity. When the water content of the clay is 10 percent , the temperature remains unchanged, and the unit pressure increases 10 times from 1961Pa to 19610Pa, ρ can drop to 65 percent of the original.
Therefore, in order to reduce the flow resistance of the grounding electrode, the backfill soil around the grounding body must be compacted 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 will cause changes in soil resistivity, and the most obvious factors affecting soil resistivity are rainfall and freezing.
In the rainy season, due to the infiltration of rainwater, the ρ of the surface soil decreases and is lower than that of the deep soil; in winter, due to the freezing effect of the soil, the ρ of the surface soil increases, which is higher than that of the deep soil.