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.

In order to analyze the adverse effect of flood affection on slope stability, the analytical expressions of buoyancy force and capillary force, hydrodynamic pressure and impact force, and scour erosion were proposed based on the aging characteristics of soil shear strength and limit equilibrium theory. According to the load combination and flood action, shear failure occurs preferentially at the foot of slope. Then, the plastic zone continues to extend upward to produce traction landslide disaster mode. Furthermore, the power function relation between shear strength index and time was established. The nonlinear accelerated creep model was also obtained. At the same time, the safety factor formula for flood loading effect slope aging stability, the time-varying characteristic value of anchor force and the compensation value of anchor force were also obtained and used to research sliding mechanism. In addition, the numerical calculation example shows that the slope safety factor decreases by more than 20 % considering the effect of flood ascending scour and impact, and the compensation value of anchorage force increases obviously with time increasing. Simultaneously, the change rate of compensation value of anchorage force increases nonlinearly with the increase of design safety factor.

Cyclic loading of deep foundations and soil anchorage elements can lead to failure by accumulation of deformations or loss of strength. Snakeskin-inspired surfaces have been shown to mobilize direction-dependent friction angles and volumetric responses due to their asymmetric profile. This paper presents an investigation on the cyclic interface element behavior of sand-structure interfaces with snakeskin-inspired surfaces with the goal of understanding the potential impact of these surfaces on the cyclic behavior of geotechnical elements. Load- and displacement-controlled cyclic interface shear tests were performed with constant stiffness boundary conditions. Four different snakeskin-inspired surfaces and reference rough and smooth surfaces were tested. The results show that under symmetric shear stress cycles, failure always takes place in the caudal direction (i.e. along the scales) due to the smaller interface friction angles. A shear stress bias can produce a change in the failure direction to the cranial one (i.e., against the scales). An equation is introduced to predict the magnitude of shear stress bias that changes the failure direction. This investigation shows that the snakeskin-inspired surfaces can be used to control the direction of failure of soil-structure interface elements which can help in increasing the cyclic stability and reducing the susceptibility of brittle failure.

Forest preservation and management are paramount for sustainable mitigation of climate change, timber production, and the economy. However, the potential of trees and forests to provide these benefits to the ecosystem is hampered by natural phenomena such as windthrow and anthropogenic activities. The aim of the current research was to undertake a critical thematic review (from 1983 to 2023) informed by a bibliometric analysis of existing literature on tree stability. The results revealed an increase in tree stability research between 2019 and 2022, with the USA, France, and Italy leading in research output, while Scotland and England notably demonstrated high research influence despite fewer publications. A keyword analysis showed that tree stability can be divided into four themes: tree species, architecture, anchorage, and environmental factors. Prominent studies on tree stability have focused on root anchorage. However, more recently, there has been a growing emphasis on urban forestry and disease-induced tree damage, underscoring a shift towards climate change and diversity research. It was concluded that considerable knowledge gaps still exist; that greater geographic diversification of research is needed and should include tropical and sub-tropical regions; that research relating to a wider range of soil types (and textures) should be conducted; and that a greater emphasis on large-scale physical modelling is required. Data and knowledge produced from these areas will improve our collective understanding of tree stability and therefore help decision makers and practitioners manage forestry resources in a more sustainable way into the future.

In this study, we analysed how the tree growth in stem and roots reacts to thinning, focusing on the consequences for mechanical stability of the root-soil plate quantified by field mechanical bending tests. In order to disentangle the role of the biomechanical control of growth (thigmomorphogenesis) from other factors, half of the studied trees were guyed to remove mechanical stimulation due to the wind of living cells. Surprisingly, our results show a decrease in the root-soil plate mechanical performances for a given stem biomass after thinning. This decrease was however explained by boosted biomass allocation to the stem at the expense of the root system. Further, relationship between the initial stiffness and the strength (overturning moment) of the root-soil plate was modified by thinning. It is suggested that at this development stage (poles), as stem break is the weakest point of tree resistance to wind loads, the biomechanical control of growth strengthens preferentially the stem and not the anchorage. Further developments should study the diversity of behaviours between development stages and between species for a unified theory on the role of the thigmomorphogenetic syndrome in tree resistance to wind risk, with synergies and trade-offs with other processes and functions.

BackgroundEarthen heritage sites have high cultural and scientific value. However, most of earthen heritage sites have been severely damaged and are in urgent need of restoration. To address this issue, a novel rockbolt, bamboo-steel composite rockbolt (BSCR), was proposed and widely employed in earthen site protection. However, the research on the anchorage mechanism of BSCR lags behind engineering practice, particularly with regard to its behavior under the coupled effect of tensile and shear stress.Case PresentationIn this study, based on centrifugal test results, a numerical model was established and validated and a comparative analysis of the anchorage mechanism between conventional rockbolt (CR) and BSCR was also conducted. Various parameters, including rockbolt diameter, bending stiffness, inclination angle, and length, were systematically investigated to elucidate their influence on protective efficacy.ConclusionBSCR has a larger diameter and bending stiffness, and is superior to CR in protecting earthen heritage sites. In addition, reducing the rockbolt inclination angle and increasing the number of rockbolt layers can reduce slope deformation caused by the coupling effect of tensile and shear stress. Increasing the length of BSCR can enhance the stability of the anchored slopes; however, due to the influence of the effective anchorage length of the rockbolt, excessively extending the rockbolt length is inefficient. These research results provide valuable insights into the application of BSCR in earthen site protection and can provide a reference for further research on its anchorage mechanism under complex stress conditions.

Plate anchors have become an attractive technology for anchoring offshore floating facilities such as floating renewable energy devices because they provide high holding capacity relative to their dry weight. This allows for the use of smaller anchors (relative to a driven or suction-installed pile), which provide cost savings on production, transport, and installation. Loads delivered to the anchor via mooring lines may increase pore water pressure in fine-grained soils. This excess pore pressure will dissipate with time, resulting in a local increase in the undrained shear strength of the soil surrounding the anchor, increasing the capacity. There may be opportunities to consider these capacity increases if the consolidation process occurs over time periods that are short relative to the lifetime of the facility. This paper considers the use of drainage channels in a plate to make the anchor permeable and quicken consolidation times. Experimental data generated from model-scale experiments conducted in a geotechnical centrifuge show (for the anchor design tested) that excess pore pressure just above the anchor dissipated almost an order of magnitude faster for a permeable anchor, and that after full consolidation, the permeable anchor capacity was higher. The latter finding was not anticipated and is believed to be due to changes in load distribution resulting from the rapid reduction in negative excess pore pressure underneath the permeable anchor.

This paper presents a comprehensive approach encompassing indoor exper-iments, theoretical analysis, and numerical simulations to investigate thedurability of prestressed anchorage structures subjected to fatigue loads andcorrosion. The study addresses the critical issue of gradual aging and dam-age caused by cumulative loads and corrosion, which ultimately leads to adecrement in structural durability. Through a rigorous analysis of the effectsof fatigue load and corrosion on the performance of steel bars, numericalsimulations were conducted to elucidate the failure mechanisms and variationpatterns within the internal anchoring section. After subjecting steel bars tofatigue and corrosion tests for a defined duration, they were systematicallycategorized and exposed to varying fatigue tensile cycles in diverse acidic andalkaline environments. Employing the PFC2D program, a numerical modelof the prestressed anchorage structure under the coupled effects of fatigueload, corrosion, and fatigue load was developed. This model allowed for acomparative analysis of the evolution of shear stress, axial stress, and dis-placement fields at the bolt-grout interface under two distinct conditions. The findings reveal the microscopic mechanisms underlying bond degradationat the bolt-grout interface under the synergistic impact of fatigue load andcorrosion. The proposed methodology and experimental results demonstratethat geotechnical anchoring technology can effectively reinforce up to 70%of geotechnical structures, significantly reducing soil loss by approximately80%. This research provides valuable insights into the durability of pre-stressed anchorage structures, paving the way for future improvements andoptimizations.