Uneven soil thickness is the biggest calamity of natural electric field drilling and water finding instrument

Soil is a mixture of water and many minerals.Because there is a lot of water and clay minerals in the soil,thus the soil layer is a very strong polar material,the ability to absorb electromagnetic waves is very strong,compared with the underlying bedrock generally shows low values,coupled with the natural electric field drilling water meter generally has a high and low value of downward transmission phenomenon,it is easy to cause false images.If some points are 1 meter thick and some points are half a meter thick,the difference between the two is 100%.The shallow layer of the thin soil layer is high value,after the downward transmission will appear high value anomaly.If the soil layer is thick,the shallow layer is a low value,and when it is transmitted down,it will be a low value anomaly,which can easily confuse the real high and low value anomalies."A difference of a millimeter is a difference of a thousand miles".This is the most frequent cause of well drilling failure,and there are numerous such cases.You must be highly cautious in hilly areas with hard rocks and thin soil layers.

For the problem of uneven thickness of the soil layer,the misalignment re-survey method is often used.Staggered retest is more important than in-situ retest,and it is difficult to exclude by doing in-situ retest only.In the limestone area,because there are often buried solution ditch solution trough,in the granite area,strong weathering degree is not uniform,some places have spherical weathering or cystic weathering,parallel staggered retesting distance,can be appropriate farther.Then is to observe the topographic changes of the survey line in the field.For example,the measurement line is a slope,one end of the line is high and one end is low,the low end of the terrain,the thickness of the soil layer may be thicker,if the value of this end becomes smaller,it should be noted.