Organic Soil Stiffness – Local Experience from Northern Poland

This paper shows an example relationship between CPTU cone resistance and oedometric modulus determined in laboratory tests. The coefficient \(\alpha\) for weak soils is proposed on the basis of local experience by comparing the results of laboratory incremental loading oedometer and in-situ cone penetrometer (CPTU) tests. Laboratory tests served as a reference, while the interpretation of CPTU results was based on averaging the values of resistance on the cone qc for a given layer. Moreover, the authors showed how large the discrepancies in the obtained value may arise during the interpretation, only due to the selection of the coefficient \(\alpha\). As cost-effective designing of the reinforcement of the soil nowadays is a difficult challenge the accurate determination of the coefficient \(\alpha\) seems to be an essential part of geotechnical surveys.