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Tracked vehicles are widely deployed for heavy lifting and transportation on inaccessible terrains such as swamps, bogs, and peatlands. The stability of a tracked vehicle is traditionally assessed only under uniaxial loading conditions and the impact of combined loading from different directions is ignored. This makes the conventional design framework somewhat unreliable. The failure envelope approach has been widely employed to assess the load- carrying capacity of shallow foundations. However, the failure envelopes available in public domain mainly focused on single isolated foundations, ignoring the interference effect between the tracks due to the rigid connection of the vehicle. This paper aims to develop an integrated framework to assess the stability of a tracked vehicle on a soft soil under fully three-dimensional loading conditions. The finite element method is adopted to simulate the soil-vehicle interactions, with the tracks idealised as two shallow foundations in parallel. The stability of the foundation system is described in terms of failure envelopes considering various track configurations and load combinations. Failure envelopes are represented by expressions and ultimately integrated into a multiple-nested function to determine the overall stability factor. The framework is demonstrated by a case study of designing a tracked vehicle under combined loading conditions. Key words: bearing capacity, soft ground, tracked vehicle, soil-vehicle interaction, combined loading, failure envelope, 1. Introduction Heavy tracked vehicles, such as excavators, trenchers, and bulldozers, are widely employed for heavy transport and operations due to their advantages in off-road performance (Fig. 1). These vehicles [...]

The editorial "Engineering Properties of Marine Soils and Offshore Foundations" discusses the importance of marine clean energy and the development of marine engineering research to extract and utilize renewable energy sources. The special issue includes 15 papers focusing on foundation treatment, offshore engineering foundations, inspection, maintenance of offshore structures, and marine resource exploitation. Various studies address topics such as subsea pipeline detection methods, coastal engineering surveys, and foundation treatment in coral reef reclamation projects. The articles aim to provide a comprehensive understanding of advancements in marine engineering research and inspire further exploration in the field. [Extracted from the article]

The evolution of a submarine landslide is a very complicated process due to slurry–water interactions. Most previous studies have focused on debris flows or turbidity currents independently. Little research has been conducted on the processes of transformation from debris flows into turbidity currents. Moreover, the underlying mechanical mechanisms of these transformation processes are not well understood. In this study, we aimed to better understand these mechanisms by simulating submarine landslide transportation processes using computational fluid dynamics. In the numerical models, the two-phase mixture module was adopted to mimic the interactions of the slurry with the ambient water, which we validated through a dam-break case. Here, the rheological behaviors of the slurries are described using the Herschel–Bulkley model. A formula for transformation rates is best fitted through a case series of debris flows. In particular, the activation stress is expressed by the dynamic pressure at the moment when the slurry starts to mobilize, which is fitted as a coefficient 6.55 × 10−5 times the shear strength. Then, two coefficients in the formula of the transformation rate are fitted as 1.61 and 0.26, respectively, based on the cases of debris flows, considering their different initial thicknesses, levels of slurry consistency and slope angles. Finally, in a real-scale debris flow case study, we demonstrate that the slurry is fully transformed before it is deposited. The expected outcome, the mechanical theory, the activation stress and the transformation rate would be applied to assess the influence area of the realistic turbidity currents and their harm to the subsea environment. [ABSTRACT FROM AUTHOR]

AbstractWith the development of offshore wind power projects worldwide, the stability of deep and shallow sea wind power sites has become a crucial concern. Internal solitary waves (ISWs) are nonlinear and large amplitude waves in the stratified ocean. Their strong vertical and horizontal motion and vorticity and turbulence caused by fragmentation have an important impact on the marine environment, seabed sediments, and marine engineering. This study focuses on the interaction between ISWs and the seabed of wind power sites in deep and shallow seas. Specifically, we investigate the interaction between ISWs and monopile foundations or floating fan plate anchor structures in the seabed. Through the simulation of CFD software and Comsol software, a law of seabed pore pressure variation during the effect of ISWs on the structure can be well demonstrated. Our results demonstrate that ISWs induce the accumulation of excess pore water pressure around the structures. The monopile foundation experiences negative excess pore water pressure at its bottom and the plate anchor at its top. The pore water pressure at the bottom of the monopile foundation initially decreases and then increases. In contrast, the pore water pressure at the right side of the monopile foundation increases, decreases, and then increases. This phenomenon promotes the settlement of the structure. At the bottom of the plate anchor, there is a sharp increase in positive excess pore water pressure by ISW. The pore water pressure above the plate anchor structure initially decreases and then increases, while below the plate anchor, it increases and then decreases. This phenomenon leads to the movement of the anchorage structure and instability of the surrounding soil. The influence of ISWs on the seabed bottom intensifies with the obstruction of the structure, resulting in significant positive pressure at the bottom. Between the two anchoring structures, there is increased seepage of pore water, making the seabed more prone to instability. Through the study of this article, we know that ISW has different effects on the force of monopile foundation and plate anchor structure, which provides a favorable basis for its design and maintenance. [ABSTRACT FROM AUTHOR]