Marly Soft Rocks: Correlation of Physical and Mechanical Properties—Examples from Dalmatia (Croatia) and Budapest (Hungary)

Soft rocks in various forms of marly materials have an important role in the geological structure of Dalmatia (Croatia) and Budapest region (Hungary). These materials can cause serious problems in design and construction, due to their complex behavior under atmospheric conditions. For the purpose of better understanding soft rocks behavior and their properties, a database with approximately 600 samples collected throughout Dalmatia was made and collated along with 260 samples from the Budapest area. Based on the collected data, 30 regression analyses were performed among 14 material properties, and eight different types of linear and non-linear correlations with high coefficients of determination were selected, which connect the important mechanical properties (uniaxial compressive strength and Young’s modulus) with physical properties of marls (porosity, dry unit weight, and ultrasonic pulse wave velocity). Most of the determined relations show symmetry between the marls from the Dalmatian region and the Budapest region, and the relation between dry unit weight and uniaxial compressive strength asymmetry can be observed between the marls with different origins. Obtained correlations may be used in cases where little or no information on geotechnical parameters is available, or where results need to be verified due to the problems present in soft rock testing.