The article presents an assessment of the suitability of the cone penetrometer to determine the soil state. The work describes the principle of the device operation, which is similar to commonly used dynamic DPL probes. Then, the results of research conducted in Polish conditions using the new conical penetrometer were presented. A series of measurements were performed in real field conditions. On their basis, an attempt was made to correlate the results obtained with a conical penetrometer and a static probe CPT. Then, the obtained correlations were validated. On this basis preliminary evaluation of the conical penetrometer suitability for the soil state determining.

This paper discusses the use of the Casagrande Cup and Cone Penetrometer Methods for determining the liquid limit of selected organic soils in in the south-eastern region of Poland in laboratory conditions in accordance with the latest standard guidelines. 10 methods established on the basis of literature materials were used to interpret the test results: 4 for test in the Casagrande Cup and 6 for the Cone Penetrometer. The results were compared and used to determine the parameters necessary to assessment of consistency of all type of soils, e.g.: plasticity index ���� (%), consistency index ���� (–) or liquidity index ���� (–). The knowledge of these parameters makes it possible to determine the degree of plasticity of the tested soils using the Cassagrande chart. The conducted research and analyses have shown that the results of determining the liquid limit using the selected methods are not always comparable. The application of calculation methods based on the results of laboratory tests organic soils carried out in accordance with the procedures of the one standard (PN-B-04481: 1988), in the case of interpretation with Method No. 5 and Method No. 7, generated results with the widest range and the highest values in relation to the reference values (Method No. 1). In terms of the suitability of a given method, the type of tested soil, extremely complicated, diverse and heterogeneous structure turned out to be important, and most importantly, the content of organic parts, as evidenced by the results of consistency determination.