Bucket foundations are considered to be environmentally friendly foundations. Their stiffness determines the resonant frequencies and fatigue life of the supported offshore wind turbines. This study proposes a rigorous three-dimensional (3D) elastic solution for the stiffness of laterally loaded bucket foundations in different soil profiles. The lumped spring stiffness acting on the top of the bucket and the exact distribution of the distributed soil spring stiffness along the bucket are first obtained from the analytical model. Closed-form formulae for the lumped spring stiffness are then fitted and verified with the existing studies. To facilitate the engineering application, the distributed soil spring stiffness is then averaged to a uniform distribution using the equivalent work method. Two types of simplified Winkler models are finally proposed and calibrated: one in which the spring stiffness is uniformly distributed along the bucket, and the other in which the distributed Winkler springs are divided into two parts bounded by the centre of rotation. The non-dimensional Winkler springs are mainly related to the bucket aspect ratio, the soil Poisson's ratio and the loading height. It is shown that the lateral soil springs alone, asp-y springs for piles, are not sufficient for bucket foundations. The combined two-part p-y springs and uniform rotational springs are suggested to obtain accurate bucket foundation responses.

Suction caisson, characterized by convenient installation and precise positioning, is becoming increasingly prevalent. Over prolonged service, a significant seepage field forms around the caisson, particularly in sandy seabed, altering the contact stress at the caisson-soil interface and causing change in the interface shear strength. Given these interface contact properties, a series of cyclic shear tests are performed, incorporating the effect of pore water pressure. Test results indicate that the interface shear strength depends on normal stress, while the interface friction angle is only minimally influenced. Drawing from the findings of the cyclic shear tests, a cyclic t-z model is established to simulate the seepage-influenced caisson-soil interface shear behavior, which is also validated at the soil unit scale through interface shear tests and at the suction caisson model scale by centrifuge tests. It is further employed to forecast the evolution of skirt wall friction for a cyclic uplifting suction caisson, showcasing the capability in capturing the foundation failure under high-amplitude cyclic loading.

With the rapid development of infrastructure in western China, numerous arch bridges have been constructed as vital transportation hubs spanning river canyons. Understanding the impact of canyon topography on the seismic response of long-span half-through arch bridges crossing canyons is essential. This study first establishes a seismic input method for oblique P-wave and SV-wave incidence, based on the viscous-spring artificial boundary theory, which transforms ground motions into equivalent nodal loads on artificial boundaries. The feasibility of this proposed method is systematically validated. Subsequently, parametric investigations are carried out to explore the effects of seismic wave incidence angle, canyon depth-to-breadth ratio and soil elastic modulus on the ground motion amplification characteristics in V-shaped canyons under oblique P-wave and SV-wave excitations. Finally, dynamic response patterns of the arch ribs and the stress-strain relationships at critical structural components are thoroughly analyzed. Key findings reveal that SV-waves induce significantly different ground motion amplification effects compared to P-waves, with the wave incidence angle and canyon width-to-depth ratio being crucial influencing factors. The connection between the arch footings and the concrete cross braces constitutes the most vulnerable region, frequently exhibiting maximum stresses that exceed the yield strength of C40 concrete under multiple scenarios. Notably, when the depth-to-breadth ratio (D/B) is 0.75, the peak stress at the arch footings reaches 5.18 x 10(7)kPa, surpassing the yield stress threshold of C40 concrete. These findings highlight the need for special seismic fortification measures at these critical connections during bridge design. This research offers valuable insights into the seismic design of long-span arch bridges in complex topographic conditions.

As critical lifeline projects, complex geological conditions affect urban buried pipelines, making their seismic safety particularly important. This study focused on a high-pressure gas pipeline project in a city to establish a static and dynamic joint analysis model of the pipeline foundation interaction system using ANSYS software. Considering various working conditions, the seismic response analysis of high-pressure pipelines under different laying methods, changes in buried depth, and bending angles was carried out. The results show the radial deformation peak of the deeply buried pipeline under the action of earthquake increases by 106.17%, which is more vulnerable to damage. The depth of soil cover significantly impacts the dynamic response of buried pipelines. Pipes should be buried shallowly, while meeting the minimum depth of soil cover and other specifications. The two 18 degrees bends are in the peak area of axial high strain, and the buried pipelines are more prone to stress concentration at the large angle bends, which should be primarily monitored. The research results can provide references for the seismic safety analysis of buried high-pressure gas long-distance pipelines in similar urban settings.

Harrow tines experience large deflections due to varying soil conditions, leading to fatigue failure through cyclic loads. Selecting the appropriate coil diameter, pitch, and number of coils is crucial for designing harrow tines that can withstand these deflections. The aim of this research is to develop new harrow tine designs that offer improved sustainability compared to conventional harrow tines used in the Canadian prairies. Nine double helical torsion spring harrow tine designs were developed, differing in coil diameters, pitch, and number of turns, while keeping the wire diameter constant. A comparative analysis was conducted, considering fatigue life, failure criteria, and stress distribution patterns assessed through Finite Element Modeling (FEM). Additively manufactured 38% scaled harrow tine prototypes underwent load-bearing tests using identical load sets of 20, 50, 100, and 200 grams. The 2T3D2P, 1T4D2.5P, and 2T4D2.5P models emerged as reliable harrow tine designs with higher fatigue life of 14,115, 14,438, and 27,618 cycles compared to the frequently used conventional harrow tine's 7533.87 cycles. Coil diameter has a preferential influence on achieving higher fatigue life, overshadowing the effects of pitch and the number of coils. Furthermore, models with larger coil diameters displayed greater flexibility against the defined weight loads, as observed in the load-bearing tests.

In cold regions, the seasonal freeze-thaw cycles constitute a significant challenge for pavement, leading to structural impairments and diminished long-term performance. During winter, the frozen water and ice formations increase pavement stiffness and bearing capacity. However, during the spring thaw, the liquid water above the frozen layer can be trapped by the impermeable frozen soil. This leads to a reduction in soil shear strength and pavement bearing capacity, resulting in deformations and damage to the roads. To mitigate these costs, Spring/Seasonal Load Restrictions (SLRs) policies have been implemented to limit axle loads and protect roads during the thaw-weakening. The success of SLR policies depends on an accurate estimation of the start date and duration of the reduced bearing capacity period. SLRs should also strike a balance between minimizing pavement damage and allowing traffic to flow freely as possible. This paper presents a comprehensive review of the existing SLR practices anssociated with their underlying mechanisms and different categories. SLR practices in Northern America are also summarized to evaluate the industry standards. In-depth discussions are added at the end based on this review to highlight the knowledge gaps and drawbacks of the current state of the practice.

High-rise pile cap structures, such as sea-crossing bridges, suffer from long-term degradation due to continuous corrosion and scour, which seriously endangers structural safety. However, there is a lack of research on this topic. This study focused on the long-term performance and dynamic response of bridge pile foundations, considering scour and corrosion effects. A refined modeling method for bridge pile foundations, considering scour-induced damage and corrosion-induced degradation, was developed by adjusting nonlinear soil springs and material properties. Furthermore, hydrodynamic characteristics and long-term performance, including hydrodynamic phenomena, wave force, energy, displacement, stress, and acceleration responses, were investigated through fluid-structure coupling analysis and pile-soil interactions. The results show that the horizontal wave forces acting on the high-rise pile cap are greater than the vertical wave forces, with the most severe wave-induced damage occurring in the wave splash zone. Steel and concrete degradation in the wave splash zone typically occurs sooner than in the atmospheric zone. The total energy of the structure at each moment under load is equal to the sum of internal energy and kinetic energy. Increased corrosion time and scour depth result in increased displacement and stress at the pile cap connection. The long-term dynamic response is mainly influenced by the second-order frequency (62 Hz).

The damage effects of the earthquake on tunnels crossing faults are categorized into two types: inertial forces generated by ground motions and permanent stratigraphic deformations caused by fault dislocations. A seismic dynamic analysis method of tunnel considering coseismic dislocation is proposed by introducing the numerical simulation of seismic wave propagation into the soil-structure dynamic analysis research field. First, seismic waves are simulated according to the finite-difference method. The stress, displacement, and velocity of nodes on the truncated boundary of the soil-structure model can be calculated according to the seismic wave propagation simulation method. Then, the seismic waves and dynamic dislocation load are simulated in the finite element model by the viscous-spring boundary. Based on the free-field model, the reliability of the presented method is validated in simulating coseismic deformation and seismic waves. In the case of the 2022 MS 6.9 Menyuan earthquake and the Daliang tunnel, which was severely damaged by this earthquake, the deformation of the tunnel simulated based on the presented method is consistent with the previous method. The proposed method can offer guidance for the seismic fortification of tunnel engineering.

The fracture network of hydraulic crack is significantly influenced by the bedding plane in coalbed methane extraction. Under mode II loading, crack deflection holds a key position in hydraulic cracking, especially in hydraulic shearing. This study first analyzed the crack deflection theory of layered rock. The semi-circle bending test under asymmetric loading is performed, and the four-dimensional Lattice Spring Model (4D-LSM) is established to examine how the bedding parameters affect coal crack propagation under mode II dominant loads. The 4D-LSM results are comparable to the coal loading test results under quasi-mode II and the analytical prediction of crack deflection theory. During mode II loading, the coal crack propagation is greatly influenced by the angle, strength, and elastic modulus of the bedding plane, while the effects of thickness and spacing of bedding are insignificant. The crack of coal tends to propagate towards the bedding, following a decrease in bedding angle, a decrease in bedding strength, and an increase in elastic modulus. With higher bedding strength, spacing, and thickness, the peak load on the coal sample is higher. The influences of bedding strength, elastic modulus, spacing, and thickness on the peak load of coal samples and its anisotropy gradually decrease. It is proved that compared with the tangential stress ratio and traditional energy release ratio theories, the corrected energy release ratio criterion can more accurately predict the direction of crack deflection of coal, especially under mode II loading. The results can provide assistance in the design of initiation pressure and fracturing direction in coal seam hydraulic fracturing. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

A discontinuous smoothed particle hydrodynamics (DSPH) method considering block contacts is originally developed to model the cracking, frictional slip and large deformation in rock masses, and is verified by theoretical, numerical and/or experimental results. In the DSPH method, cracking is realized by breaking the virtual bonds via a pseudo-spring method based on Mohr-Coulomb failure criteria. The damaged particles are instantaneously replaced by discontinuous particles and the contact bond between the original and discontinuous particles is formed to simulate the frictional slip and separation/ contraction between fracture surfaces based on the block contact algorithm. The motion of rock blocks and the contact force of discontinuous particles are determined following Newton's second law. The results indicate that the DSPH method precisely captures the cracking, contact formation and complete failure across six numerical benchmark tests. This single smoothed particle hydrodynamics (SPH) framework could significantly improve computational efficiency and is potentially applicable to broad multi-physical rock engineering problems of different scales. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).