Mechanical responses of anchoring structure under triaxial cyclic loading

Dynamic load on anchoring structures(AS)within deep roadways can result in cumulative damage and failure.This study develops an experimental device designed to test AS under triaxial loads.The device enables the investigation of the mechanical response,failure mode,instability assessment criteria,and anchorage effect of AS subjected to combined cyclic dynamic-static triaxial stress paths.The results show that the peak bearing strength is positively correlated with the anchoring matrix strength,anchorage length,and edgewise compressive strength.The bearing capacity decreases significantly when the anchorage direction is severely inclined.The free face failure modes are typically transverse cracking,concave fracturing,V-shaped slipping and detachment,and spallation detachment.Besides,when the anchoring matrix strength and the anchorage length decrease while the edgewise compressive strength,loading rate,and anchorage inclination angle increase,the failure intensity rises.Instability is determined by a negative tangent modulus of the displacement-strength curve or the continued deformation increase against the general downward trend.Under cyclic loads,the driving force that breaks the rock mass along the normal vector and the rigidity of the AS are the two factors that determine roadway stability.Finally,a control measure for surrounding rock stability is proposed to reduce the internal driving force via a pressure relief method and improve the rigidity of the AS by full-length anchorage and grouting modification.

Mechanism of high-preload support based on the NPR anchor cable in layered soft rock tunnels

The control of large deformation problems in layered soft rock tunnels needs to solve urgently.The roof problem is particularly severe among the deformation issues in tunnels.This study first analyzes the asymmetric deformation modes in layered soft rock tunnels with large deformations.Subsequently,we construct a mechanical model under ideal conditions for controlling the roof of layered soft rock tunnels through high preload with the support of NPR anchor cables.The prominent roles of long and short NPR anchor cables in the support system are also analyzed.The results indicate the significance of high preload in controlling the roof of layered soft rock tunnels.The short NPR anchor cables effectively improve the integrity of the stratified soft rock layers,while the long NPR anchor cables effectively mobilize the self-bearing capacity of deep-stable rock layers.Finally,the high-preload support method with NPR anchor cables is validated to have a good effect on controlling large deformations in layered soft rock tunnels through field monitoring data.

Anchoring mechanical characteristics of Ductile-Expansion bolt

The application of ductile rock bolts has been a crucial method for solving the problems of large deformations,energy absorption and stability control issues in deep rock masses.To study the anchoring mechanism of the key expansive structure,this paper proposes a novel type of bolt—the Ductile-Expansion bolt,and conducts research on anchoring mechanics,energy absorption characteristics,and failure modes of the bolt.In addition,this paper defines the concept of load-volume ratio of metal rock bolts and proves the Ductile-Expansion bolt is capable of better improving the unit volume bearing capacity of the bolt material.Furthermore,laboratory and field tests verify the Ductile-Expansion bolt had better anchoring effect than the traditional rebar bolt,with the expansion structure favorably enhancing the ductility and energy absorption performance of the bolt.Finally,this paper microscopically analyzes the crack propagation and distribution morphology of the bolts by establishing a 3D coupled numerical model based on FDM-DEM.Numerical results illustrate the interface at the variable diameter of the Ductile-Expansion bolt serves as the transition zone between high and low stress levels.The expansion structure can impose radial compression on the medium around the bolt,which can improve the bolt anchorage performance.

Seismic stability of expansive soil slopes reinforced by anchor cables using a modified horizontal slice method

Earthquake-induced slope failures are common occurrences in engineering practice and pre-stressed anchor cables are an effective technique in maintaining slope stability,especially in areas that are prone to earthquakes.Furthermore,the soil at typical engineering sites also exhibit unsaturated features.Explicit considerations of these factors in slope stability estimations are crucial in producing accurate results.In this study,the seismic responses of expansive soil slopes stabilized by anchor cables is studied in the realm of kinematic limit analysis.A modified horizontal slice method is proposed to semi-analytically formulate the energy balance equation.An illustrative slope is studied to demonstrate the influences of suction,seismic excitations and anchor cables on the slope stability.The results indicate that the stabilizing effect of soil suction relates strongly to the seismic excitation and presents a sine shape as the seismic wave propagates.In higher and steeper slopes,the stabilizing effect of suction is more evident.The critical slip surface tends to be much more shallow as the seismic wave approaches the peak and vice versa.

Case study on the mechanics of NPR anchor cable compensation for large deformation tunnel in soft rock in the Transverse Mountain area,China

A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced during the tunnel construction.To mitigate this problem,a support system was designed incorporating negative Poisson ratio(NPR)anchor cables with negative Poisson ratio effect.Physical model experiments,field experiments,and numerical simulation experiments were conducted to investigate the compensation mechanical behavior of NPR anchor cables.The large deformations of soft rocks in the Daliangshan Tunnel are caused by a high ground stress,a high degree of joint fracture development,and a high degree of surrounding rock fragmentation.A compensation mechanics support system combining long and short NPR anchor cables was suggested to provide sufficient counter-support force(approximately 350 kN)for the surrounding rock inside the tunnel.Comparing the NPR anchor cable support system with the original support system used in the Daliangshan tunnel showed that an NPR anchor cable support system,combining cables of 6.3 m and 10.3 m in length,effectively prevented convergence of surrounding rock deformation,and the integrated settlement convergence value remained below 300 mm.This study provides an effective scientific basis for resolving large deformation problems in deeply buried soft rocks in western transverse mountain areas.

Exploring the feasibility of prestressed anchor cables as an alternative to temporary support in the excavation of super-large-span tunnel

Excavating super-large-span tunnels in soft rock masses presents significant challenges.To ensure safety,the sequential excavation method is commonly adopted.It utilizes internal temporary supports to spatially partition the tunnel face and divide the excavation into multiple stages.However,these internal supports generally impose spatial constraints,limiting the use of large-scale excavation equipment and reducing construction efficiency.To address this constraint,this study adopts the“Shed-frame”principle to explore the feasibility of an innovative support system,which aims to replace internal supports with prestressed anchor cables and thus provide a more spacious working space with fewer internal obstructions.To evaluate its effectiveness,a field case involving the excavation of a 24-m span tunnel in soft rock is presented,and an analysis of extensive field data is conducted to study the deformation characteristics of the surrounding rock and the mechanical behavior of the support system.The results revealed that prestressed anchor cables integrated the initial support with the shed,creating an effective“shed-frame”system,which successively maintained tunnel deformation and frame stress levels within safe regulatory bounds.Moreover,the prestressed anchor cables bolstered the surrounding rock effectively and reduced the excavation-induced disturbance zone significantly.In summary,the proposed support system balances construction efficiency and safety.These field experiences may offer valuable insights into the popularization and further development of prestressed anchor cable support systems.

Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion

Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous research.This study focuses on a more comprehensive combination failure mode that consists of bond failure of an anchorage body and failure of an anchored rock mass.The three-dimensional ultimate pullout capacity of the anchor cables is calculated based on the Hoek-Brown failure criterion and variation analysis method.The numerical solution for the curvilinear function in fracture plane is obtained based on the finite difference theory,which more accurately reflects the failure state of the anchor cable,as opposed to that being assumed in advance.The results reveal that relying solely on a single failure mode for UPC calculations has limitations,as changes in parameter values not only directly impact the UPC value but also can alter the failure model and thus the calculation method.

Mechanical behavior of 2G NPR bolt anchored rock samples under static disturbance loading

The deep mining of coal resources is accompanied by severe environmental challenges and various potential engineering hazards.The implementation of NPR(negative Poisson's ratio)bolts are capable of controlling large deformations in the surrounding rock effectively.This paper focuses on studying the mechanical properties of the NPR bolt under static disturbance load.The deep nonlinear mechanical experimental system was used to study the mechanical behavior of rock samples with different anchored types(unanchored/PR anchored/2G NPR anchored)under static disturbance load.The whole process of rock samples was taken by high-speed camera to obtain the real-time failure characteristics under static disturbance load.At the same time,the acoustic emission signal was collected to obtain the key characteristic parameters of acoustic emission such as acoustic emission count,energy,and frequency.The deformation at the failure of the samples was calculated and analyzed by digital speckle software.The findings indicate that the failure mode of rock is influenced by different types of anchoring.The peak failure strength of 2G NPR bolt anchored rock samples exhibits an increase of 6.5%when compared to the unanchored rock samples.The cumulative count and cumulative energy of acoustic emission exhibit a decrease of 62.16%and 62.90%,respectively.The maximum deformation of bearing capacity exhibits an increase of 59.27%,while the failure time demonstrates a delay of 42.86%.The peak failure strength of the 2G NPR bolt anchored ones under static disturbance load exhibits an increase of 5.94%when compared to the rock anchored by PR(Poisson's ratio)bolt.The cumulative count and cumulative energy of acoustic emission exhibit a decrease of 47.16%and 43.86%,respectively.The maximum deformation of the bearing capacity exhibits an increase of 50.43%,and the failure time demonstrates a delay of 32%.After anchoring by 2G NPR bolt,anchoring support effectively reduces the risk of damage caused by static disturbance load.These results demonstrate that the support effect of 2G NPR bolt materials surpasses that of PR bolt.

Clinical feasibility of laparoscopic left lateral segment liver resection with magnetic anchor technique:The first clinical study from China

BACKGROUND Magnetic anchor technique(MAT)has been applied in laparoscopic cholecystectomy and laparoscopic appendectomy,but has not been reported in laparoscopic partial hepatectomy.AIM To evaluate the feasibility of the MAT in laparoscopic left lateral segment liver resection.METHODS Retrospective analysis was conducted on the clinical data of eight patients who underwent laparoscopic left lateral segment liver resection assisted by MAT in our department from July 2020 to November 2021.The Y-Z magnetic anchor devices(Y-Z MADs)was independently designed and developed by the author of this paper,which consists of the anchor magnet and magnetic grasping apparatus.Surgical time,intraoperative blood loss,intraoperative accidents,operator experience,postoperative incision pain score,postoperative complications,and other indicators were evaluated and analyzed.RESULTS All eight patients underwent a MAT-assisted laparoscopic left lateral segment liver resection,including three patients undertaking conventional 5-port and five patients having a transumbilical single-port operation.The mean operation time was 138±34.32 min(range 95-185 min)and the mean intraoperative blood loss was 123±88.60 mL(range 20-300 mL).No adverse events occurred during the operation.The Y-Z MADs showed good workability and maneuverability in both tissue and organ exposure.In particular,the operators did not experience either a“chopstick”or“sword-fight”effect in the single-port laparoscopic operation.CONCLUSION The results show that the MAT is safe and feasible for laparoscopic left lateral segment liver resection,especially,exhibits its unique abettance for transumbilical single-port laparoscopic left lateral segment liver resection.

Minimum 10-year follow-up outcomes of arthroscopic Bankart’s repair with metallic anchors:Reliable results with low redislocation rates

BACKGROUND With stiff competition from alternative albeit more expensive counterparts,it has become important to establish the applicability of metallic anchors for shoulder instability in the modern era.This can be accomplished,in part,by analysing long-term outcomes.AIM To analyse minimum 10-year outcomes from 30 patients following arthroscopic anterior stabilisation using metallic anchors.METHODS Prospectively collected data from arthroscopic Bankart repairs performed using metal anchors during 2007P-2010 were retrospectively analysed in this singlesurgeon study.Comprehensive data collection included historical and clinical findings,dislocation details,operative specifics,and follow-up radiological and clinical findings including shoulder scores.The primary outcomes were patientreported scores(Constant,American Shoulder and Elbow Surgeons[ASES],and Rowe scores)and pain and instability on a visual analogue scale(VAS).RESULTS A 3% recurrence rate of dislocation was noted at the final follow-up.Total constant scores at 10 years postoperatively measured between 76 and 100(mean 89)were significantly better than preoperative scores(mean 62.7).Congruous improvements were also noted in the Rowe and ASES scores and VAS at the 10-year review.CONCLUSION Reliable long-term outcomes with metallic anchors in surgery for shoulder instability can be expected.Our results provide additional evidence of their continued,cost-effective presence in the modern scenario.

Research on the Influence of Anchor Attributes on Consumers’Online Behaviors in Social E-Commerce Platforms:The Moderating Effect of Platform Contextual Factors

As e-commerce continues to mature,the advantages of live streaming within the industry have become increasingly apparent,offering significant growth opportunities.Social e-commerce platforms,which are user-centered,integrate social networks with e-commerce by leveraging social interactions to drive product sales and enhance the overall consumer shopping experience.This type of e-commerce fosters engagement and promotes products by merging online communities with shopping behavior,creating a more interactive and dynamic marketplace.It not only retains the traditional e-commerce trading and marketing functions but also adds a social dimension,making live stream anchors crucial figures connecting consumers with products.These anchors can attract consumers with their appearance and charm,and use their expertise on live streaming platforms to guide consumers by recommending live content.They can also interact with their audiences and potentially influence them to purchase the recommended goods.It is evident that the attributes of anchors in live streaming rooms significantly impact consumers’online behavior.Therefore,researching how platform contextual factors regulate consumers’online behavior is of great practical significance.This study employs multilevel regression analysis to support its hypotheses using data.The findings indicate that contextual factors of the platform significantly influence online behavior,enhancing the positive relationship between user attachment and online activities.

Anchor-free目标检测算法综述

目标检测作为计算机视觉领域的基础,其研究价值对于推动人工智能发展具有重要意义。长期以来,许多学者都致力于提升目标检测算法效率及性能的研究,无锚点(anchor-free)的目标检测深度学习算法以尺度灵活、鲁棒性强等优势,开始逐渐广泛应用于目标检测任务。介绍了目标检测领域中卷积神经网络和Transformer两种经典的网络架构;以核心网络架构为分类标准,分别介绍了基于卷积神经网络和基于Transformer的anchor-free目标检测深度学习算法,总结了这些算法的改进点和优缺点,并对该方向的未来发展及应用做出展望。

IRNet:基于Anchor-Free的地面红外目标检测方法

地面红外目标检测是目标侦察、智能感知和伪装防护等领域的重要研究内容,针对基于锚框的目标检测模型在进行特征提取时需要锚框的指导,会产生大量与锚框有关的计算参数并导致检测不精细、泛化性能差、易发生误检漏检的问题,以基于图像分割思想的无锚框目标检测模型为基础,构建了基于可变形卷积进行特征提取的主干网络,通过卷积核自适应目标形态,增强网络对目标特征的提取效果;提出了联合空间和通道的注意力机制,从空间维度和通道维度对目标进行注意力聚焦,实现了对目标特征的三维关注,提升目标检测模型对目标信息的获取能力。最终构建的地面红外目标检测模型在Infrared-VOC数据集上检测精度达到了91.3%,优化了基于无锚框的地面红外目标检测模型的整体性能。

基于anchor-free的光学遥感舰船关重部位检测算法

针对基于深度学习的遥感舰船检测算法存在精细化程度不足、检测效率低的问题,提出一种基于anchor-free的光学遥感舰船关重部位检测算法。所提算法以全卷积的单阶段目标检测(FCOS)算法为基准,在主干网络中引入全局上下文模块,提高网络的特征表达能力;为更好地描述目标的方向性,在预测阶段构建了具有方向表征能力的回归分支;对中心度函数进行优化,使其具备方向感知和自适应能力。实验结果表明:在自建舰船关重部位数据集和HRSC2016上,所提算法的平均精度(AP)比FCOS算法有显著提升;与其他算法相比,所提算法在检测速度和检测精度上均表现优越,具有较高的检测效率。

缝合锚钉经内踝修复三角韧带深层损伤

背景:踝关节骨折合并三角韧带损伤在临床上较为常见,骨折内固定一期修复三角韧带逐渐成为主流治疗方法,明显降低了踝关节远期并发症的发生。近年来在三角韧带解剖结构特征和动态生物力学研究领域取得新进展,使三角韧带深层损伤修复技术有了较大提高,但仍存在争议。目的:探讨缝合锚钉技术与经内踝修复踝关节骨折合并三角韧带深层损伤的临床疗效。方法:选择中南大学湘雅医学院附属海口医院2017年1月至2022年1月收治的踝关节骨折合并三角韧带深浅层完全断裂的56例患者,依据带线锚钉修复三角韧带深层的方式不同分为2组,其中缝合锚钉修复组32例,经内踝修复组24例。对两组患者手术治疗前后的踝关节内侧间隙、美国矫形外科足踝协会评分进行评定。结果与结论:①56例患者均顺利完成手术并获得术后12个月以上随访,踝部骨折均愈合,骨折愈合时间8-12周,平均10.5周;②两组患者术后12个月踝关节内侧间隙较术前显著缩小,差异有显著性意义(P<0.001);术后12个月,两组踝关节内侧间隙维持在正常范围,组间对比差异无显著性意义(P>0.05);③术后6,12个月,两组患者美国矫形外科足踝协会评分较术前显著升高(P<0.001),相应时间点,两组美国矫形外科足踝协会评分相比差异均无显著性意义(P>0.05);④提示缝合锚钉技术与经内踝修复三角韧带深层损伤均能恢复踝关节内侧间隙、有效维持踝穴的稳定性,获得良好的临床疗效。

Anchor钉重建伸肌腱止点治疗锤状指

目的 探讨治疗锤状指的手术方法。方法 对12例锤状指的患者采用Anchor钉重建伸肌腱止点的手术方法治疗。结果术后随访2-12个月，11例患者于术后6周左右复查X线片均未见骨锚松动、脱落；术后8周远侧指间关节活动自如。结论使用Anchor钉重建伸肌腱止点治疗锤状指，具有操作简单、肌腱修复可靠、术后并发症少的优点，是一种值得推广的手术方法。

Anchor free与Anchor base算法结合的拥挤行人检测方法

由于精度相对较高,Anchor base算法目前已成为拥挤场景下行人检测的研究热点。但是,该算法需要手工设计锚框,限制了其通用性。同时,单一的非极大值抑制(NMS)筛选阈值作用于不同密度的人群区域会导致一定程度的漏检和误检。为此,该文提出一种Anchor free与Anchor base检测器相结合的双头检测算法。具体地,先利用Anchor free检测器对图像进行粗检测,将粗检测结果进行自动聚类生成锚框后反馈给区域建议网络(RPN)模块,以代替RPN阶段手工设计锚框的步骤。同时,通过对粗检测结果信息的统计可得到不同区域人群的密度信息。该文设计一个行人头部-全身互监督检测框架,利用头部检测结果与全身的检测结果互相监督,从而有效减少被抑制与漏检的目标实例。提出一种新的NMS算法,该方法可以自适应地为不同密度的人群区域选择合适的筛选阈值,从而最大限度地减少NMS处理引起的误检。所提出的检测器在CrowdHuman数据集和CityPersons数据集进行了实验验证,取得了与目前最先进的行人检测方法相当的性能。

Mitek Anchor系统锚钉置入辅助加固修复急性闭合性跟腱断裂:2年同一机构12例资料回顾

12例急性闭合性跟腱断裂患者采用改良Kessler法修补跟腱,后用Mitek Anchor钉各1枚置于跟腱内外侧跟骨内,采用Bunnell方法将尾线由远向近穿经跟腱断端,加固缝合后的跟腱。随访伤口愈合情况、负重行走时间、足跟部疼痛和跟腱再断裂情况,采用Arner-Lindholm方法评价踝关节功能。修补后未见切口感染或者皮肤坏死病例。12例患者锚钉置入辅助加固修补跟腱后随访14-25个月,平均17个月。无足跟部疼痛和再断裂发生,根据Arner-Lindholm踝关节功能评定标准,优4例,良8例。结果提示,采用Mitek Anchor系统辅助加固治疗急性闭合性跟腱断裂,跟腱修补后可早期负重,降低了跟腱再断裂发生率,是一种理想的治疗方法。

Anchor Attachment蛋白在结直肠癌中表达增强

目的探讨Anchor Attachment蛋白(AAP)的表达与结直肠癌浸润、转移的关系及临床意义。方法免疫组织化学法检测AAP的表达,分析AAP表达水平与肿瘤临床病理特征之间的关系;并用酶联免疫吸附(ELISA)法检测血清中AAP表达水平。结果结直肠正常肠黏膜、癌原发灶、淋巴结和肝转移灶中AAP的表达阳性率分别为20.5%、53.0%、69.8%和80.0%;癌原发灶、转移淋巴结和肝转移灶中AAP表达阳性率均显著高于正常肠黏膜组织(P<0.01),转移淋巴结和肝转移灶中AAP阳性率高于癌原发灶(P<0.05);淋巴结转移患者和肝转移患者的原发灶AAP阳性率显著高于无转移者(P<0.01);Dukes分期A、B、C、D期患者AAP阳性率逐渐增高,各分期之间差异显著(P<0.01)。83例结直肠癌患者血清AAP水平为(6.3±2.8)μg/L,显著高于30例健康志愿者的(2.2±0.9)μg/L,(t=6.976,P<0.01);Dukes分期A、B期患者血清AAP水平为(5.2±2.6)μg/L,显著低于C、D期患者的(7.1±2.9)μg/L(P<0.05)。结论检测外周静脉血AAP水平对预测和判断结直肠癌病情和肝转移有重要意义。

Anchor钉在肩关节脱位并肩袖损伤中应用的疗效观察

目的探讨Anchor钉在肩关节脱位并肱骨大结节撕脱性骨折及肩袖损伤中应用的疗效。方法13例肩关节脱位并肱骨大结节撕脱性骨折及肩袖损伤患者行经三角肌一胸大肌入路显露骨折端，以Anchor钉行Krackow缝合方法结合钛钉内固定进行治疗。随访评价其肩关节稳定性、活动范围、上肢肌力、影像学改变。结果所有患者得到随访，随访时间10—16个月，平均12个月，骨折均愈合良好。肩关节功能按Neer评分法，优11例，良2例。结论Anchor钉结合钛钉修复肱骨大结节撕脱性骨折及肩袖损伤固定牢固、术后可早期功能锻炼，肩关节功能恢复良好，是一种较理想的手术方法。