Suction anchor foundations serve as a critical anchoring solution for submerged floating tunnel (SFT) cable systems. In marine environments, these foundations must endure not only static loads but also long-term oblique cyclic loading caused by wave excitation, which can result in soil weakening and a reduction in bearing capacity. This study systematically examines the oblique cyclic bearing behavior of SFT suction anchors using a combined experimental and numerical approach. The results demonstrate that (1) the cyclic load ratio initially increases with increasing wave periods, then decreases, before rising again; (2) displacement accumulation at the mooring point occurs rapidly during the initial wave loading cycles, gradually stabilizing as cycling progresses; (3) during foundation failure, tension redistribution displays asymmetric characteristics, with connected cables experiencing load reduction while adjacent cables are subjected to amplified forces; (4) numerical analyses quantify key parametric relationships, revealing that the weakening coefficient (alpha) decreases with increasing loading angle, exhibits a positive correlation with zeta b, and shows a negative correlation with zeta c. These findings advance the understanding of cyclic performance in SFT anchors and offer essential insights for SFT safety evaluations.

Drag embedded anchors (DEA) are widely used in offshore engineering. The anchor foundations are installed in the seabed through the drag force applied by the mooring line and provide holding capacity to marine structures. Offshore wind farms in Taiwan are located in active earthquake zones, where a considerable amount of sandy soil at the upper layer of seabed results in a high potential for soil liquefaction. Since DEA are a promising option for floating wind turbines, this study conducted a shaking table test on two 1/30-scale anchors in medium dense sand to investigate the dynamic behavior of DEA during earthquakes and after excess pore water pressure dissipation. The test results reveal no significant impact on the orientation of the anchors, which could be due to the uplift force from the excess pore water pressure acting on the fluke. After the excess pore water pressure dissipates, the soil density increases, and the fluke angle becomes favorable, thus increasing the anchor's holding capacity when subjected to additional drag.

This paper investigates the pullout behaviours of horizontal rectangular plate anchors under inclined loading in sand using three - dimensional finite element (3D-FE) analysis. An advanced bounding surface plasticity model incorporating the critical state framework is developed to capture the stress-strain relationship of sand. The model is firstly validated against various analytical solutions and centrifuge test data. Then, a series of FE analysis is conducted to consider the effects of plate anchor aspect ratio, initial embedment depth, sand relative density and inclined loading angle on the pullout capacities. Results show that shallow anchors develop failure zones reaching the soil surface, and vertical pullout capacity exceeds that under pure vertical loading when the load is slightly inclined. For deep anchors, failure zones are confined below the surface, and horizontal pullout capacity exceeds that under pure horizontal loading when the load is slightly inclined. The transitional embedment depth depends on anchor aspect ratio and sand density. A modified analytical solution is proposed to estimate the vertical pullout capacity of plate anchors from shallow to deep depths. Failure envelopes established from probe tests provide practical guidance for assessing rectangular anchor failures under various inclined loadings.

The experimental studies were performed to examine the failure mechanism and the capacity of BFRP bolt-anchorage system under laboratory and field conditions in supporting clay slopes in Sichuan Basin, China. The results indicate that BFRP anchor bolts, designed based on the principle of equal strength replacement between bolt tensile strength and the bonding strength of the first interface, can meet the safety standards required for slope engineering. During the stable phase of the slope, the mechanical behavior and deformation characteristics of BFRP anchor bolts are comparable to those of steel anchor bolts, with the axial force of BFRP bolts being 1/3 to 1/4 lower than the designed value. When the slope enters the accelerated creep stage, the axial force of steel anchor bolts exceeds the designed value by 40 %, while the axial force of BFRP bolts remains at only 2/3 of that of steel bolts. The failure mechanisms of the BFRP bolt-anchorage system primarily involve shear failure at the bolt-mortar interface and pullout failure of the bolt body, which are attributed to the cumulative damage of the polymer material. Based on the experimental findings, it is recommended that the minimum tensile safety factor for BFRP bars used in temporary slope support should be set at 1.26. This study enhances the understanding of BFRP anchorage systems in clay soil environments and provides valuable insights for the design and construction of infrastructure projects in similar geological conditions.

The prestressed glass fiber-reinforced polymer (GFRP) rock bolt, characterized by its lightweight, high-strength, fatigue-resistant, and corrosion-resistant, effectively addresses the durability challenges associated with rock bolts in soil applications. This study was based on the shear test of GFRP anchor rods under varying levels of prestressing. The present study designed and conducted shear tests on GFRP anchor bolt joint surfaces under varying prestress levels, utilizing the double shear test method. Based on the experimental results, this research analyzed the influence of prestress on failure modes, shear bearing capacity, and shear deformation of GFRP anchor bolt joint surfaces. Furthermore, by employing an equivalent strain assumption in conjunction with damage mechanics theory, a predictive model for shear displacement-shear stiffness and shear displacementshear stress was established for GFRP anchor bolts. The results indicated that the failure mode of the prestressed GFRP anchor rod joint surface shear specimen was the shear failure following the splitting of the GFRP anchor rod. The shear carrying capacity of the joint surface with 20 % and 40 % pre-stressed GFRP anchor rods increased by 8.2 % and 20.3 % compared to the non-prestressed anchor rod, respectively. However, the ultimate displacements decreased by 22.7 % and 49.7 %, respectively. The initial stiffness of the 20 % and 40 % prestressed GFRP anchor rods was higher than that of non-prestressed GFRP anchor rods. However, under shear loading, the fracture strain of prestressed GFRP anchor rods decreased by 33 % and 44 %, respectively, compared to non-prestressed counterparts. The shear displacement-shear stiffness and shear displacement-shear stress relationships of prestressed GFRP anchor rods under the action of shear load were found to conform to the exponential distribution and Weibull distribution, respectively. The mechanical models proposed in this paper for shear displacement-shear stiffness and shear displacement-shear stress could effectively predict the mechanical behavior of shear damage on the joint surface of prestressed GFRP anchor rods.

Rainfall-induced landslide mitigation remains a critical research focus in geotechnical engineering, particularly for safeguarding buildings and infrastructure in unstable terrain. This study investigates the stabilizing performance of slopes reinforced with negative Poisson's ratio (NPR) anchor cables under rainfall conditions through physical model tests. A scaled geological model of a heavily weathered rock slope is constructed using similarity-based materials, building a comprehensive experimental setup that integrates an artificial rainfall simulation system, a model-scale NPR anchor cable reinforcement system, and a multi-parameter data monitoring system. Real-time measurements of NPR anchor cable axial forces and slope internal stresses were obtained during simulated rainfall events. The experimental results reveal distinct response times and force distributions between upper and lower NPR anchor cables in reaction to rainfall-induced slope deformation, reflecting the temporal and spatial evolution of the slope's internal sliding surface-including its generation, expansion, and full penetration. Monitoring data on volumetric water content, earth pressure, and pore water pressure within the slope further elucidate the evolution of effective stress in the rock-soil mass under saturation. Comparative analysis of NPR cable forces and effective stress trends demonstrates that NPR anchor cables provide adaptive stress compensation, dynamically counteracting internal stress redistribution in the slope. In addition, the structural characteristics of NPR anchor cables can effectively absorb the energy released by landslides, mitigating large deformations that could endanger adjacent buildings. These findings highlight the potential of NPR anchor cables as an innovative reinforcement strategy for rainfall-triggered landslide prevention, offering practical solutions for slope stabilization near buildings and enhancing the resilience of building-related infrastructure.

Helical anchors are deep foundation systems that offer high uplift capacity due to the increased interaction area between the helix and surrounding soil, thus exhibiting strong potential for resisting frost jacking in cold-region engineering. The influence of helical anchor geometry on frost heave behavior remains a critical yet insufficiently understood factor in engineering designs. Accordingly, this study conducts experimental and numerical investigations to evaluate the effects of helix number, helix diameter, helix spacing, and freeze-thaw cycles on frost jacking and thaw-induced settlement. The results indicate that the frost jacking and residual displacement after thawing gradually decrease with increasing freeze-thaw cycles and tend to stabilize after more than three cycles. Numerical simulations show that the residual displacements for full-scale anchors range from 12% to 33% of the peak frost jacking. Anchors with a greater number of helices demonstrate improved resistance to frost jacking when the uplift capabilities are comparable. When the helix spacing ranges from 2D to 6D (where D denotes the helix diameter), the double-helix anchor with 2D spacing exhibits the highest stability during freeze-thaw cycles, followed by the anchor with 3D spacing. However, the anchor with 2D spacing yields the lowest uplift capacity under unfrozen soil conditions. Anchors with a helix spacing of 2D to 3D are recommended for resisting freeze-thaw effects, provided that this configuration does not significantly reduce the uplift capacity.

As transmission lines extend into mountainous regions, engineering practices must address the challenging geological conditions of soil-over-weathered-rock strata and the complex loads imposed by extreme climates. This study introduces a novel perimeter anchor pier composite foundation designed specifically for soil-weathered rock strata, aimed at optimizing the mechanical performance of piles and anchors. Initially, material pretests were conducted to determine the appropriate proportions and mechanical properties for scaled models. Subsequently, tension-compression-bending loading tests were performed to investigate the deformation and failure patterns of the novel foundation. Finally, by analyzing the deformation and failure characteristics of the piles and test data, load-displacement-failure curves for the composite structure were derived. The results show that under compression-bending loads, cracks penetrate the pier, causing splitting failure of the pier body and shearing failure of the short piles at the base. Under tension-bending loads, the base short piles experience tensile rupture without damaging the rock mass, while the anchor undergoes significant deformation. The study also reveals that the load-bearing capacity of the base rock mass is not fully utilized, and it recommends enhancing pile strength to improve the overall bearing capacity of the perimeter anchor pier composite foundation.

The anchor is commonly applied to enhance the seismic stability of a slope. Presently, the seismic permanent displacement of slope is widely estimated with a constant yield acceleration based on Newmark sliding block method, which is not a realistic scenario. Besides, the soil slope is mostly inhomogeneous and anisotropic, where a circular slip surface is not quite suitable for slope stability analysis. To overcome the shortcomings of estimation method of earthquake-induced displacement, a point-to-point strategy is applied to generate the instant discrete failure mechanism of inhomogeneous and anisotropic anchored slope to determine the time-dependent yield acceleration by limit analysis. The recursive formulas of slope and anchor parameters versus seismic displacement at tiny time interval are established to predict the dynamic behavior of slope. The seismic displacement at tiny time interval is estimated by Newmark sliding block method, and the total earthquakeinduced displacement is subsequently determined. The anchor axial force increases significantly during seismic excitation, which causes a time-dependent characteristic of yield acceleration. Moreover, the effect of inhomogeneity and anisotropy is investigated. The slope becomes more vulnerable to earthquake while the inhomogeneity of unit weight is considered. An increment in inhomogeneous factor or a decrement in anisotropic factor of friction angle or cohesion causes the stability of anchored slope to increase.

The issue of water-enriched surrounding rock induced by excavation disturbances in loess tunnels represents a significant challenge for the construction of loess tunnel projects. Based on the concepts of lime sac water absorption, expansion, and compaction, consolidation, and drainage of surrounding rock and soil, as well as active reinforcement, a tandem water-absorbing and compaction anchor with heat-expansion and compaction consolidation functionality has been developed. To facilitate the engineering design and application of this novel anchor, a consolidation equation for cylindrical heat source-consolidated soil was derived under conditions of equal strain and continuous seepage. Considering the impact of temperature in the thermal consolidation zone on soil permeability, an analytical solution for the average degree of consolidation of the surrounding soil after support with the water-absorbing and compaction anchor was provided. The correctness of the solution was verified through engineering examples, demonstrating the reasonableness of the theoretical calculation method used in this study. The analysis of consolidation effects in engineering examples demonstrates that the excess pore water pressure in the borehole wall area dissipates rapidly after reaming, exhibiting an exponential decay over time. By the 100th time step, the pore pressure decreases from 100 kPa to 63.2 kPa. As consolidation continues, by the 1000th time step, the pore pressure further reduces to 21.6 kPa. The region with significant changes in pore pressure amplitude is primarily located within the plastic zone of the reamed hole, while the rate of pore pressure change in the more distal elastic zone is generally lower. The consolidation process effectively dissipates the excess pore water pressure and converts it into effective stress in the soil, indicating a notable active reinforcement effect of the water-absorbing compaction anchor. Within the plastic zone, the attenuation rate of excess pore water pressure is 85%. Under different drainage conditions at the borehole wall, the dissipation rate of excess pore pressure in Model 1 (Assuming drainage conditions around the water absorbing anchor rod) is greater than that in Model 2 (Assuming that there is no drainage around the water absorbing anchor rod), with the average degree of consolidation in Model 1 being 22% higher than in Model 2. Under the conditions of Model 1, the active reinforcement effect of the water-absorbing compaction anchor is more pronounced, providing better reinforcement for the surrounding rock and soil. To ensure the reinforcement effect, the theoretical design should consider a certain surplus in the filling quality of the lime water-absorbing medium. The research findings are of significant importance for advancing the theoretical structural design and engineering practical application of this new type of anchor.