Impact pile driving is widely employed in various environments. The soil surrounding driven piles undergoes large shear displacements and highly cyclic loads, leading to significant strength degradation. This paper introduces a novel soil reaction model with easily calibrated parameters to estimate the pile penetration performance under continuous impact driving, incorporating both cyclic degradation and base gap. Soil cumulative plastic displacement is utilized to quantity the degradation, enabling more accurate simulation of cyclic pile response. The model is integrated into the pile driving system and applied in multiple-blow analysis. Non-linear cumulative displacement-blow count curves are analyzed and the development of residual stress varies between the pile upper and lower sections. It is found that lower blow counts are required when cyclic degradation is considered, although the increased rebound effect may counterbalance this benefit. Comparative analyses for degradation constants further demonstrate that early-stage degradation has a more pronounced impact. Finally, the proposed model is also adopted to predict blow count in field practice, offering valuable insights for driveability analysis.

As offshore wind turbines approach the end of their operational lifespan, the decommissioning process is gaining increasing importance, which highlights the need to develop expertise in the marine operations involved in this task. This study focuses on simulating the vibratory extraction of a monopile foundation for an offshore wind turbine using a crane barge. A numerical model is developed to couple the dynamic behavior of the monopile with that of the barge. To accurately represent soil behavior during the extraction process, a high-fidelity finite element model is first established to calculate the soil resistance component under high-frequency cyclic loading generated by the vibro-hammer. Then, time domain numerical simulations of the monopile decommissioning process are carried out, and an external Dynamic Link Library (DLL) is developed to integrate this soil resistance force into the time-domain program. Additionally, the centrifugal force exerted by the vibro-hammer is incorporated into the model through a separate DLL. Time-domain simulations are performed to analyze the barge's motion and the tension in the lifting wire under calm water conditions. These results are then compared with simulations conducted under long-crested waves to provide a comprehensive understanding of the extraction process. This study also examines the effect of the dynamic positioning system on the barge's dynamic response and the tension in the lifting wire. The outcome of this paper contributes to a better understanding of the complex decommissioning process under marine environments.

The resistance of compacted soils is a mechanical property related to various parameters and that in many cases does directly depend on only dry density value as field control measures. In considerable soils this property is complex to specify and requires a more detailed study. In this work, the characterization of the resistance of a soil used in the construction road embankments is carried out, applying the tools of the Rational Methodology for the Analysis of Densification and Resistance of Compacted Geomaterials, with the purpose of knowing, through a novel approach, the mechanical response the soil related to different physical variables measurable during the construction process, among them, humidity and percentage of compaction. A CBR testing program was established as a resistance parameter, with specimens manufactured with their own conditions of humidity and compaction energy defined by the proposed factorial experiment. From the results, graphs of great engineering value were obtained, such as resistance maps for the interpretation of the mechanical manifestation of the material studied and the representation of a spectrum of design curves for the selection of the CBR following a weighting procedure and according to the possible hydration conditions associated with the project location.

In the article, based on the derived equations for the smooth distribution of the flowing current along the ground electrodes of electrical protection systems, a method is proposed for calculating the service life and the permissible current load on it, which, unlike conventional calculations, does not lead to an overestimation or underestimation of the service life and the permissible load current and takes into account the method of connection cable to the ground electrode.

Fastening of hydrotechnical oil-gas mining facilities to seabed soils in Caspian Sea aquatoriums is usually carried out by pile foundations. Sustainability of strength and stability during the design and construction of hydraulic structures requires to solve a number of theoretical and practical problems. Numerous static and dynamic tests (experiments) were carried out in the Caspian Sea aquatorium and in laboratory conditions to solve these issues. The widespread use of pile foundations in the development of offshore oil and gas fields revealed the inconsistency of the domestic scientific methodological and regulatory framework for calculating their load-bearing capacity over the soil. It is established that the wave strikes, acting on pile foundations, interact with the surface design of offshore structures and offshore ground bases. Sea wave banging pile foundations creates vibrations in the pile foundation - topsides offshore structures and moving piles in subgrade. Displacement piles depend on the strength of the reaction between the structure and subgrade, the intensity of the shock wave in the time that passed through piles for offshore soil. At the same time, it takes into account the rheological properties of composite models of shelf soil.