The stability of tailings dams is governed predominantly by the physical properties and geotechnical behavior of their primary construction material—tailings. Consequently, a systematic understanding of these characteristics is of great significance for the rational design and long-term stable operation of tailings dams. This review focuses on the physical properties and geotechnical behavior observed in different types of tailings. In terms of physical properties, the particle size distribution exhibits a pronounced hydraulic classification characteristic within the impoundment, consisting predominantly of silt-sized particles and displaying an overall trend toward finer gradation. The mineralogical and chemical composition is dominated by quartz, hematite, and silicates. However, significant spatial variability exists both between different tailings types and across distinct zones within the same tailings pond. Regarding geotechnical behavior, the permeability of tailings is governed by a fines content threshold: below this threshold, permeability decreases with increasing fines content, while beyond it, the permeability stabilizes. When studying consolidation and compression behavior using slurry specimens, the compression curves exhibit nonlinear characteristics, primarily described by the modified Gibson theory. The shear behavior of tailings is significantly influenced by confining pressure, drainage conditions, anisotropy and stress paths. The presence of transitional behavior leads to the critical state line determined based on a single sampling method erroneously assessing the dilation/cosntraction characteristics of in situ tailings, thereby affecting the assessment of liquefaction risk. Future research should focus on the seepage, consolidation and shear properties of clayey fine-grained tailings and unsaturated tailings, and aim to elucidate the key controlling factors of transitional behavior to enhance the reliability of tailings dam stability assessments.

Tailings are solid waste generated during mining and mineral processing. Their tremendous accumulation not only encroaches on arable land but also pollutes the environment. Currently, tailings are considered a viable alternative to natural fine aggregates in concrete because of their suitable physicochemical properties. However, existing studies remain highly fragmented and often report inconsistent conclusions owing to the considerable variability in tailings mineralogy, particle morphology, and physicochemical characteristics. To date, a comprehensive synthesis linking these intrinsic properties to the fresh, mechanical, durable, microstructural, environmental, and economic performance of tailings concrete remains lacking. Therefore, this review provides a systematic and critical assessment of tailings as aggregate in concrete and proposes an integrated framework connecting tailings characteristics, microstructural evolution, engineering performance, and sustainability outcomes. It systematically examines the physico-mechanical properties, durability, microstructure, hydration characteristics, environmental impact, and economic benefits of the resulting tailings concrete. The results showed that although tailings varied considerably in particle size, chemical composition, and mineralogy, they typically exhibited a rough surface texture and high water absorption. Furthermore, partial substitution of fine aggregates with tailings was found to improve the physical–mechanical properties and durability. However, to prevent performance decline, the substitution ratio should not exceed 50%. These benefits originated primarily from the filling effect and optimized particle packing, which increased matrix density. Microstructural analyses indicated that moderate tailings contents refined the pore structure, strengthened the interfacial transition zone (ITZ), and promoted hydration. In contrast, excessive substitution ratios weakened bonding and increased porosity. From an environmental perspective, the use of tailings generally reduced carbon emissions (by up to ~28%) and production costs (by up to ~50%) by lowering natural resource consumption and enabling large-scale waste valorization. Overall, tailings represent a sustainable aggregate alternative, provided that substitution levels are carefully controlled to balance workability, performance, and durability.

The reasonable construction state of a cable-stayed bridge refers to the state achieved after construction is carried out according to a specific sequence of procedures, leading to the reasonable completion status the bridge. The corresponding construction states at each stage are considered as part of the reasonable construction state. For the optimization of the construction state of cable-stayed bridges with steel box girders, a method combining a multi-objective programming algorithm with a forward iteration method is proposed to determine a reasonable construction state based on the structural characteristics and optimization principles of such bridges. First, a multi-objective programming model was established, taking the bending moments of the main girder and pylon, as well as cable forces, as objective functions. The weighted square sum method, a type of evaluation function method, was then employed to convert the multi-objective programming model into an unconstrained single-objective quadratic programming model. Subsequently, the damped Newton method was utilized to solve the quadratic programming problem. By integrating this algorithm with the forward iteration method, the reasonable construction state of a large-span and double-tower steel box girder cable-stayed bridge was optimized. The influence of different objective functions on the optimization results was analyzed. The findings demonstrate that the proposed method produces a smooth structural configuration under the optimized construction state, with internal forces and normal stresses within a reasonable range. In the completed state derived from this construction state, internal forces, normal stresses, and cable forces are uniformly distributed, while the reactions at transition piers and auxiliary piers exhibit sufficient pressure reserves. The structural state under dead load achieved through this method closely aligns with the desired reasonable completed state.

Helical anchors represent a promising solution for anchor systems of floating offshore wind turbines, yet scour-induced changes to the seabed threaten anchor stability. The bearing capacity and failure mechanisms of helical anchors under such conditions have not been fully investigated. Finite element (FE) analyses examine scour geometry, anchor length, and soil heterogeneity (κ = kD/s_um, where k is the undrained strength gradient, D is the shaft diameter, and s_um is the surface strength). The results demonstrate that scour depth is the dominant factor governing bearing capacity, whereas scour width and slope angle have limited effects. Horizontal capacity is particularly sensitive to scour because the corresponding failure mechanism develops mainly within shallow soil. Increasing κ mitigates scour-induced capacity loss, with this effect being most pronounced as κ rises from 0 to 2, beyond which further increases yield diminishing benefit. Across different helical anchor embedment lengths, scour is shown to shift the critical embedment depth separating shallow and deep failure mechanisms, particularly under low soil heterogeneity. The effects of loading direction are further evaluated within the V-H loading space. Finally, predictive expressions are developed to capture the coupled effects of scour geometry, soil heterogeneity, and anchor length for engineering capacity assessment.

Strike-slip fault misalignment can lead to stress concentration, fissure development, and slip instability in overlying soil layers, triggering geologic hazards such as surface displacement, landslides, and rock formation deformation, causing severe damage to buried infrastructure. In cross-regional energy transmission projects, stress concentration and deformation failure induced by fault movement in cross-fault buried pipelines critically threaten the safe transmission of oil and gas. As the scale of oil and gas pipeline construction in China expands, pipelines inevitably cross fault zones, increasing rupture risk and necessitating investigation of fault misalignment mechanisms and pipeline mechanical response. This study employs three-dimensional nonlinear finite element analysis to investigate the mechanical response of X80 buried pipelines under strike-slip fault action. A comprehensive pipe-soil interaction model incorporating the Ramberg-Osgood constitutive relationship and Mohr-Coulomb soil plasticity is developed using ABAQUS software. The research systematically examines the effects of fault displacement (0.5-2.5 m), pipeline wall thickness (18.4-32.1 mm), internal pressure (0-12 MPa), and pipe-soil friction coefficient (0.3-0.6) on pipeline stress and strain responses. Key findings include: (1) a characteristic bimodal von Mises stress distribution occurs at approximately ±20 m from the fault plane, with secondary peaks at ±10 m; (2) stress and strain increase nonlinearly with fault displacement, with diminishing increments as the material enters the plastic regime; (3) increasing wall thickness from 18.4 mm to 32.1 mm reduces maximum tensile strain by approximately 50 %; (4) internal pressure and friction coefficient effects are significant only below the 2 m fault displacement threshold. The results provide quantitative guidelines for wall thickness selection and protective measure implementation for cross-fault pipeline design, ensuring safe operation during service life.