The resistivity of soil is one of the important indexes to judge the corrosion of soil, which comprehensively reflects the corrosion factors such as water content and dissolved salt content in soil.
Relationship between soil resistivity and soil corrosion
Soil resistivity > 50 20~50 < 20
Soil corrosion is low to medium strong
A four - column resistance meter is required to measure soil resistivity. Taking the isometric method as an example, the specific steps are as follows: ① Lay four ground electrodes equidistant along a straight line in the measured area. If the electrode spacing is S, the insertion depth of the electrodes is 1/20s. (2) The instrument is placed smoothly, and the 4 terminals are connected with the 4 electrodes in sequence. (3) Shake the handle of the instrument to ensure the speed of about 120R /min, adjust the ratio and the measuring panel, so that the needle of the meter head points to the line in the center. ④ Read the quantity disk data and multiply it with the multiplier, and the value is R. ⑤ According to the formula P = 2πsr, the calculated result is the average soil resistivity from the surface to the depth S, and the unit is ω.m