Method and system for determining a soil class and use during determination of a soil class

A method for determining one or more soil classes in a given area of interest without performing a geological sample analysis on said area, the method comprising:

• drilling an earth borehole in said given area by means of a horizontal ground drilling device using a drilling head of a given type selected from one or more different types;
• setting operating parameters of the horizontal ground drilling device for operation of the horizontal ground drilling device for drilling at least a portion of the earth borehole with the selected drilling head, the operating parameters comprising the torque, tensile/compressive force, speed of advancement, mud-flush rate and rotational speed;
• during said drilling of said borehole in said area of interest, determining by a programmed control system of the horizontal ground drilling device, a given soil class present in the portion of the earth borehole being drilled, based on the drilling head type used, and said operating parameters, in association with a database of soil classifications which associates soil classes with drilling head type, and the operating parameters, said given soil class comprising at least one of a grain size soil class, a grain size distribution soil class, a water content soil class, a plasticity and consistency soil class, an organic substance soil class, a hardness soil class, and a solubility soil class present in the portion of the earth borehole being drilled;
• wherein the programmed control system exerts influence on the horizontal ground drilling device's machine control to optimize the process of creating the horizontal earth borehole;
• determining location points of the drilling head during said drilling operation, and
• correlating said received location points of the drilling head with the determined soil class, to thereby map the determined one or more soil classes over the select area of interest,
• wherein said determining said given soil class present is performed upon sensing a change in one or more of the type of drilling head being used and said at least one set operating parameter.