Despite the widespread use of Ultrasonic Pulse Velocity (UPV) to estimate the dynamic properties of materials, the accuracy of its results for concrete and rock cylinders, even though it does not depend on cylinder slenderness, is directly affected by the a priori assumption of a specific value of the Poisson's ratio ( ), which can lead to errors of up to 50% in the calculation of the dynamic modulus of elasticity (E_d). In contrast, the Impact Echo (IE) method allows the calculation of E_d without the need-to-know Poisson’s ratio, with an error of approximately 2%, but its results are affected not only by the slenderness ratio (L/D) but also by the inertia effect and the mass of the sensor. In this study, both UPV and IE—longitudinal and torsional—tests were carried out on cylindrical steel and aluminium specimens for six different slenderness values and L/D values ranging from 1-5. The experimental results fully confirm the authors’ proposed shape correction factor (SCF). A numerical analysis of short cylinders is conducted to examine how the mass of the accelerometer used on the IE affects the results. Specifically, aluminium and steel specimens with six different slenderness values were simulated via the finite element method (FEM) via experimental evaluation. Inertia and mass interactions significantly affect the results. Two new correction factors were proposed for steel and aluminium cylinders to address this issue, and three different combinations of NDTs were tested to find that the dynamic properties are very sensitive to these parameters. Poisson’s ratio has been accurately calculated for steel and aluminium cylinders and can be calculated for concrete and rock cores by applying the proposed correction factors.

The integration of new technologies across scientific disciplines, including rock slope engineering, is increasingly essential. The use of drones and advanced software tools for mapping and analyzing large rocky slopes in detail has become indispensable and highly beneficial. In this context, this paper examines the process and key parameters involved in generating a high-resolution 3D terrain model and evaluating rock-mass stability using advanced software tools (UgCS version 5.5.0, ArcGIS version 3.4.3, Drone2Map version 2024.2.1, DSE version 3.02, and Rocfall3D version 1.014). These technologies facilitate the identification of hazard zones on rocky slopes in monuments of archaeological interest. The evaluation of this modeling approach is conducted at the monolithic rock of Ancient Corinth (Acrocorinth), one of Greece’s most significant archaeological sites. This study focuses on assessing its vulnerability to rockfalls and identifying hazard zones. This methodology involves the development of a 3D rockfall analysis system and the implementation of a specialized hazard matrix for the quantitative assessment of rockfall risk. This approach enables the development of a decisive model for mitigating rockfall hazards, ensuring the safety of visitors in high-traffic areas such as major archaeological sites.

Many significant landslide movements are often observed in the upper weathering zone of flysch, which constitutes the most critical landslide-prone geological formation in Western Greece. In this article, a laboratory approach is adopted to investigate the behavior of highly weathered and tectonically decomposed flysch for slope stability analyses with the performance of large shear testing in reconstituted soil specimens. The testing program included several reconstituted flysch specimens derived from three representative landslides. Tests under large direct shearing (300 × 300 × 120 mm) were conducted in moisture- and density-controlled conditions and ring shear tests were conducted in the finer material. The test results revealed that the values of the effective angle of friction in the flysch material decrease with the increasing water content. Moreover, dense specimens showed curved failure envelopes due to dilatancy, especially in dry conditions. A comparison of laboratory test results with those obtained by performing back-analyses under saturated conditions has shown that the sliding of the weathered and decomposed flysch mainly depends on its residual angle of friction which was found to be 1°–6° lower than the ultimate angle of friction as it was estimated by the large shear tests.

Biochar is a stable carbon-rich material produced from carbon-rich biomass in the absence of air or under oxygen-limited conditions. A plethora of feedstocks can be used to produce biochar including wood-based materials, organic wastes (i.e. sludges, manure), plant-based materials (i.e, leaves, seeds, husks) as well as food-waste residues or by-products. In addition, pyrolysis conditions such as temperature, heating rate, duration and the scale the pyrolysis system, also vary considerably. Therefore, biochars differ widely in their physical and chemical characteristics. Biochar is recommended as a soil amendment due to its ability to enhance the physicochemical characteristics of soil and support crop growth.Biochar influences soil in various ways. It can raise pH, enhance cation exchange capacity, increase extractable nutrients, modify microbial communities and soil processes, and improve physical traits like bulk density and structure, supporting better plant growth. This study reviews the factors that influence the interaction of soil and biochar in terms water retention. The analysis shows that biochar generally reduces soil bulk density and improves water retention, especially in coarse‑textured soils where field capacity, wilting point, and available water increase substantially. Effects are smaller in medium soils and minimal in fine soils.

Non-destructive in-situ tests, such as the plate bearing (plate load) test, are widely used to estimate the equivalent deformation modulus (e.g., E_v2) of existing road embankments. However, the depth of influence sampled by such a test is governed by the loading plate diameter, so a single test yields only an average, diameter-dependent modulus rather than the actual variation of stiffness with depth. This study investigates whether systematically varying the plate diameter, and inverting the resulting settlement–diameter (dispersion) curves, can recover the full depth-dependent stiffness profile, E(z). Synthetic settlement–diameter curves were generated using a Boussinesq-based forward model for four families of reference stiffness profiles, representing normal (stiffness increasing with depth) and reverse (stiffness decreasing with depth) linear and exponential trends, combined with six Poisson’s ratios and five profile slopes/exponents (30 cases per profile family, 120 cases in total). Two inversion strategies were applied to back-calculate E(z) from each dispersion curve: a classical Occam-type, smoothness-constrained (Tikhonov-regularized) nonlinear inversion, and a direct, closed-form Simplified Inversion Method (SIM) based on differencing the apparent-modulus-versus-diameter curve. Results were benchmarked against the known reference profiles. Once calibrated so that its governing parameters depend only on Poisson’s ratio and the shape of the measured dispersion curve, SIM could be applied blindly, without prior knowledge of the true profile, and recovered E(z) with markedly lower error than Occam’s inversion (WAD = 2.2–4.7% and RMSPE = 2.6–5.8%, versus 7.4–19.1% and 9.4–28.3%, respectively, across the four profile families). For the Poisson’s ratio most typical of earth materials, ν = 0.3, the calibration further collapses to a universal parameter set (I = 0.66; c = 1.3 for stiffness increasing with depth, c = 2.5 for stiffness decreasing with depth), which attains WAD ≤ 4.2% across all four families with no calibration equation at all. Notably, Occam’s inversion reproduced the settlement–diameter curve itself with good accuracy in most cases, yet this close data fit did not guarantee an accurate stiffness profile—a direct manifestation of the intrinsic non-uniqueness of the settlement-based inverse problem. These findings support the use of a Poisson ratio-calibrated direct inversion method as a practical, robust alternative to generic regularized inversion for recovering stiffness profiles from multi-diameter plate loading data.