Generating soil layers

Generate Soil Layers command analyzes cone or friction values to generate soil segments (layers). By means of the criteria a CPT can be defined into a number of segments. Here the basic assumption should be applied: the geotechnical parameters for every segment have a constant value. This segment arrangement shows some similarities with a soil drilling.

Determining a soil segment arrangement based on cone tip resistances and/or the local sleeve friction values allows several interpretations as:

  • Generation of the soil materials based on  the friction values;
  • Generation of the soil materials based on the cone tip resistance range [qc;inf – qc;sup] analysis;
  • Generation of the soil materials based on the cone tip resistance [qc] values.

 

Basic information concerning the soil properties is by default represented in the NEN-EN 1997-1 table 2b. Using the soil Geotechnics Settings, user defined soil material table(s) could be created and used for the soil segment arrangement generation.

Generation of the soil material segment arrangement performed using the friction values [wc;inf – wc;sup] or cone tip resistance range [qc;inf – qc;sup] analysis is based on the best fit with the average value within the boundaries. In case value persist for the soil recognition is defined outside the range(s), recognition analysis is interrupted or could be continued using  the cone tip resistance [qc] or the average friction values. The soil material segment arrangement, performed using the cone tip resistance [qc] values, is based on the looking of the nearest magnitude defined in the Soil materials table.

If multiple soils are defined that have the same Qc or Wc value, then the first soil in the list with that value will be used. In case it is necessary to reorder soils, a new table should be created and soils ordered as appropriate, or soils with same Qc/Wc values could be deleted

Using the soil material table(s), the geotechnical designer should have sufficient knowledge of the structure of the soil composition and if required he should make the necessary inquiries for example by using soil drilling or by consulting geological maps.