signal interpretation methods, examining, above all, the time domain approaches and considering the influence of FF content. However, the inconclusive results from the bender element (BE) tests highlight the complexity of factors affecting shear wave velocity, which requires further research to refine the methodology and assess long-term performance in geotechnical applications. Selecting the correct test frequency and interpretation method is crucial to obtain accurate results. The BE test method should consider all relevant factors. At low input frequencies (≤5 kHz), the near-field effect affected the received signal for fRCA mixtures. At higher frequencies (around 14 kHz), the noise levels increased, thereby interfering with the S-wave travel time determination. Intermediate input frequencies (10.0 and 12.5 kHz) provided the representative shear modulus (G) values. The small-strain shear modulus (Gmax) of the fRCA compounds from the resonant column and BE tests was found to be in good agreement, despite differences in the test procedures themselves.

investigations should include planning tests that allow for determining the maximum number of geotechnical parameters, such as cone penetration tests (CPTU) or Marchetti dilatometer tests (DMT). The article presents the in situ tests aimed at assessing the relative density of sandy soils. Empirical formulas available in the literature for determining the relative density Dr from DMT gave inconsistent results compared to those obtained from dynamic soundings, especially in the near-surface zone, where high KD readings significantly overestimate relative density values. Assuming the results of DPL probe tests as reference values, a formula for the compaction index based on DMT soundings has been proposed. In contrast to the formulas commonly used in the literature, the proposed formula for the relative density depends not only on the horizontal stress index KD, but also on the dilatometer modulus ED.

W pracy wykorzystano wyniki badań terenowych, głównie CPT oraz DMT, które porównano z wynikami badań laboratoryjnych pobranych próbek gruntów. Proponowana metoda podziału warstw geotechnicznych wraz z doborem odpowiednich parametrów gruntowych dla wydzielanych warstw zakłada zastosowanie podejścia bayesowskiego.

local conditions. The paper uses the results of in situ tests, mainly CPT and DMT, which were compared with the results of laboratory tests. A Bayesian approach was used in proposing a technique for subdividing the geotechnical layers with the annotation of the relevant parameters for the separated layers.