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Mechanical responses of anchoring structure under triaxial cyclic loading 被引量:2
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作者 Peng Wang Nong Zhang +5 位作者 Qun Wei Xingliang Xu Guangzhen Cui Aoran Li Sen Yang Jiaguang Kan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期545-560,共16页
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 inves... 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. 展开更多
关键词 Triaxial stress Dynamic-static combination load Cyclic loading anchoring structure(AS) Cumulative damage
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Mechanism of high-preload support based on the NPR anchor cable in layered soft rock tunnels 被引量:1
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作者 SUI Qiru HE Manchao +3 位作者 SHI Mengfan TAO Zhigang ZHAO Feifei ZHANG Xiaoyu 《Journal of Mountain Science》 SCIE CSCD 2024年第4期1403-1418,共16页
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 d... 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. 展开更多
关键词 Tunnel engineering Soft rock High-preload support NPR anchor cables
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Anchoring mechanical characteristics of Ductile-Expansion bolt
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作者 Yu Chen Wang Liu +4 位作者 Linchong Huang Hang Lin Yixian Wang Yanlin Zhao Cungang Lin 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第8期1115-1134,共20页
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... 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. 展开更多
关键词 Ductile-Expansion bolt Pull-out test Peak load anchoring mechanical characteristics
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Seismic stability of expansive soil slopes reinforced by anchor cables using a modified horizontal slice method
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作者 Wang Long Chen Guoxing +3 位作者 Hu Wei Zhou Enquan Feng Jianxue Huang Anping 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期377-387,共11页
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 earthquak... 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. 展开更多
关键词 limit analysis expansive soil slope matric suction anchor cable pseudo-dynamic analysis
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Case study on the mechanics of NPR anchor cable compensation for large deformation tunnel in soft rock in the Transverse Mountain area,China
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作者 LI Yong ZHENG Jing +3 位作者 HUO Shu-sen WANG Feng-nian HE Man-chao TAO Zhi-gang 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第6期2054-2069,共16页
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 duri... 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. 展开更多
关键词 soft rock large deformation NPR anchor cable physical model numerical simulation compensation mechanics
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Exploring the feasibility of prestressed anchor cables as an alternative to temporary support in the excavation of super-large-span tunnel
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作者 Shunhua Zhou Yuyin Jin +3 位作者 Zhiyao Tian Chunhua Zou Heming Zhao Zengrun Miao 《Railway Engineering Science》 EI 2024年第3期344-360,共17页
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 partit... 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. 展开更多
关键词 Super-large-span tunnel Construction safety Sequential excavation method Shed-frame principle Prestressed anchor cables
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Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion
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作者 ZUO Shi ZHAO Lianheng HU Shihong 《Journal of Mountain Science》 SCIE CSCD 2024年第3期1036-1047,共12页
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 combinat... 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. 展开更多
关键词 anchor cable Ultimate pullout capacity(UPC) Failure model Variation analysis Hoek-Brown failure criterion
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On the calibration of a shear stress criterion for rock joints to represent the full stress-strain profile
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作者 Akram Deiminiat Jonathan D.Aubertin Yannic Ethier 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期379-392,共14页
Conventional numerical solutions developed to describe the geomechanical behavior of rock interfaces subjected to differential load emphasize peak and residual shear strengths.The detailed analysis of preand post-peak... Conventional numerical solutions developed to describe the geomechanical behavior of rock interfaces subjected to differential load emphasize peak and residual shear strengths.The detailed analysis of preand post-peak shear stress-displacement behavior is central to various time-dependent and dynamic rock mechanic problems such as rockbursts and structural instabilities in highly stressed conditions.The complete stress-displacement surface(CSDS)model was developed to describe analytically the pre-and post-peak behavior of rock interfaces under differential loads.Original formulations of the CSDS model required extensive curve-fitting iterations which limited its practical applicability and transparent integration into engineering tools.The present work proposes modifications to the CSDS model aimed at developing a comprehensive and modern calibration protocol to describe the complete shear stressdisplacement behavior of rock interfaces under differential loads.The proposed update to the CSDS model incorporates the concept of mobilized shear strength to enhance the post-peak formulations.Barton’s concepts of joint roughness coefficient(JRC)and joint compressive strength(JCS)are incorporated to facilitate empirical estimations for peak shear stress and normal closure relations.Triaxial/uniaxial compression test and direct shear test results are used to validate the updated model and exemplify the proposed calibration method.The results illustrate that the revised model successfully predicts the post-peak and complete axial stressestrain and shear stressedisplacement curves for rock joints. 展开更多
关键词 Full shear profile Post-peak shear behavior Rock joint Joint roughness coefficient(JRC) Axial stress-strain curve
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Mechanical behavior of 2G NPR bolt anchored rock samples under static disturbance loading
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作者 WANG Jiong JIANG Jian +4 位作者 WANG Siyu CHANG Yiwen LIU Peng HE Manchao CHENG Shuang 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2494-2516,共23页
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 lar... 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. 展开更多
关键词 anchored rock samples Static disturbance load Acoustic emission characteristics Digital speckle Negative Poisson's ratio
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Clinical feasibility of laparoscopic left lateral segment liver resection with magnetic anchor technique:The first clinical study from China
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作者 Miao-Miao Zhang Ji-Gang Bai +7 位作者 Dong Zhang Jie Tao Zhi-Min Geng Zhuo-Qun Li Yu-Xiang Ren Yu-HanZhang Yi Lyu Xiao-Peng Yan 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第5期1336-1343,共8页
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 ... 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. 展开更多
关键词 Magnetosurgery/magnetic surgery Magnetic anchor technique Laparoscopic hepatectomy Transumbilical singleport laparoscopy Magnet
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Minimum 10-year follow-up outcomes of arthroscopic Bankart’s repair with metallic anchors:Reliable results with low redislocation rates
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作者 Prateek Kumar Gupta Vishesh Khanna +1 位作者 Nikunj Agrawal Pratyaksh Gupta 《World Journal of Methodology》 2024年第2期88-96,共9页
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 a... 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. 展开更多
关键词 Long-term outcomes Arthroscopic Bankart repair Metallic anchors Low failure rates
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Research on the Influence of Anchor Attributes on Consumers’Online Behaviors in Social E-Commerce Platforms:The Moderating Effect of Platform Contextual Factors
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作者 Xiaodong Yang Gi Young Chung 《Proceedings of Business and Economic Studies》 2024年第5期186-193,共8页
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,in... 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. 展开更多
关键词 anchor attribute User attachment Consumers’online behaviors Contextual factors
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Anchor-free目标检测算法综述
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作者 陈恒星 刘一鸣 《机电工程技术》 2024年第8期7-12,共6页
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... 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。 展开更多
关键词 目标检测 anchor-free 卷积神经网络 TRANSFORMER
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IRNet:基于Anchor-Free的地面红外目标检测方法
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作者 徐叶斌 赵晓枫 +3 位作者 刘少龙 夏玉婷 张文文 郑超 《电光与控制》 CSCD 北大核心 2024年第12期72-77,90,共7页
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... 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。 展开更多
关键词 深度学习 地面红外目标检测 智能感知 无锚框 可变形卷积 并联注意力机制
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基于anchor-free的光学遥感舰船关重部位检测算法
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作者 张冬冬 王春平 付强 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2024年第4期1365-1374,共10页
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... 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。 展开更多
关键词 深度学习 遥感图像 anchor-free 舰船检测 关重部位检测 全卷积单阶段检测
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Anchor free与Anchor base算法结合的拥挤行人检测方法 被引量:5
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作者 谢明鸿 康斌 +1 位作者 李华锋 张亚飞 《电子与信息学报》 EI CSCD 北大核心 2023年第5期1833-1841,共9页
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... 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。 展开更多
关键词 行人检测 anchor base anchor free 非极大值抑制
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基于Anchor-free的图像全景分割算法研究
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作者 陈颖 秦怡芳 张艳硕 《计算机应用与软件》 北大核心 2023年第10期255-260,290,共7页
对于实例分割子任务,大多数框架都采用基于anchor的策略,如著名的Mask R-CNN。但anchor依赖于人为预先设置,且由于anchor和RPN的存在,网络计算量往往很大。设计一个自定义的U-Net骨干网络和一个立足于极坐标系对实例分割掩膜边缘进行数... 对于实例分割子任务,大多数框架都采用基于anchor的策略,如著名的Mask R-CNN。但anchor依赖于人为预先设置,且由于anchor和RPN的存在,网络计算量往往很大。设计一个自定义的U-Net骨干网络和一个立足于极坐标系对实例分割掩膜边缘进行数学建模的anchor-free的实例分割网络,将二者集成到全景分割架构中去。该全景分割网络摆脱人工预设的anchor,实现轻量级,U-Net骨架网相比FCN网干网在精度相差不多的情况下参数量下降35%,更适合低开销实时应用场景。 展开更多
关键词 全景分割 实例分割 无锚框 极坐标系 自定义U-Net
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Application of a new basalt fiber-reinforced polymer anchorage structure in the tunnel–slope system under rainfall action 被引量:1
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作者 TANG Lin WU Hong-gang +2 位作者 WEI Hong FENG Kang RENG Guo-jun 《Journal of Mountain Science》 SCIE CSCD 2023年第2期570-584,共15页
The application of basalt fiber-reinforced polymer(BFRP)anchors has gained significant attention,particularly in the field of geotechnical anchorage engineering because of its high strength and corrosion resistance.Th... The application of basalt fiber-reinforced polymer(BFRP)anchors has gained significant attention,particularly in the field of geotechnical anchorage engineering because of its high strength and corrosion resistance.The research on the applicability of BFRP anchor in a tunnel–slope system under rainfall is of practical significance to solve the problem of instability damage to anchored slopes caused by corrosion of steel anchors.In this study,model tests of BFRP and steel anchorage structures were conducted to compare their reinforcement capability in a tunnel–slope system under heavy rainfall.The results show that the BFRP anchorage structure is better than the steel in coordinating slope deformation and stabilizing earth pressure around the tunnel.The deformation of slopes under rainfall is classified into four stages:initial,isokinetic,accelerated,and blocked deformations.BFRP anchors have the same axial strain distribution pattern as the steel anchors,and they are convexly distributed along the axial direction of the anchors.The correlation analysis and Pearson linear correlation analysis of the multi-attribute data of the slope and BFRP anchors showed a positive correlation among BFRP anchor strain,earth pressure inside the slope,slope deformation displacement,and accumulated rainfall.These research results provide a basis and reference for the application of BFRP anchors in the anchorage engineering of the tunnel–slope system under rainfall action. 展开更多
关键词 BFRP anchors Steel anchors RAINFALL Tunnel-slope system
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Strength characteristics of rock anchored by NPR bolt with different preloads 被引量:2
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作者 SUN Xiao-ming CUI Li +2 位作者 ZHANG Yong WANG Lei JIANG Ming 《Journal of Mountain Science》 SCIE CSCD 2023年第3期834-844,共11页
This study compares the strength characteristics of rocks anchored by NPR bolts and ordinary bolts with varied preloads,based on the mechanical properties of NPR bolts(with a negative Poisson’s ratio).The results sho... This study compares the strength characteristics of rocks anchored by NPR bolts and ordinary bolts with varied preloads,based on the mechanical properties of NPR bolts(with a negative Poisson’s ratio).The results show that the uniaxial compressive stress-strain curve of ordinary anchored rocks exhibits noticeable abrupt changes.After reaching peak strength,the bolt breaks,whereas the stress-strain curve of NPR-anchored rocks is smoother.The NPR bolt enters the stage of continuous resistance after reaching maximal strength and does not break.As the preload increases,the strength of the anchored rock grows linearly.A calculation equation for the strength of the anchored rock is proposed based on the preload.The theoretical equation fits the test results well,and the fitted parameters show that NPR bolts can better increase the strength of the rock.The concept of dynamic toughness UC of anchored rock is proposed to reflect the comprehensive mechanical properties of anchored rock,including strength and plasticity.As the preload increases,the UC of ordinary anchored rock first decreases and then increases,while the UC of the NPR anchored rock does not change significantly with the preload when the strain is small,and the UC increases with the increase of the preload when the strain is large. 展开更多
关键词 NPR bolt anchored rock Rock bolt Uniaxial compression PRELOAD Strength characteristics
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Full-scale pullout tests of rock anchors in a limestone quarry focusing on bond failure at the anchor-grout and grout-rock interfaces 被引量:2
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作者 Bjarte Grindheim Charlie CLi Are Håvard Høien 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第9期2264-2279,共16页
Rock anchors are a common safety measure for stabilising large-scale infrastructure,such as bridge towers,retaining walls,rock slopes and windmills.There are four principal failure modes for rock anchors:(a)tensile fa... Rock anchors are a common safety measure for stabilising large-scale infrastructure,such as bridge towers,retaining walls,rock slopes and windmills.There are four principal failure modes for rock anchors:(a)tensile failure of the steel anchor,(b)anchor-grout interface failure,(c)grout-rock interface failure,and(d)rock mass uplift.Field tests were performed in a limestone quarry.These tests were designed to test failure modes B and C through pullout.In the tests of failure mode B,the shear stress on the anchor-grout interface is the largest at the top of the grout column and attenuates towards the distal end for small loads.The shear stress becomes uniformly distributed when the applied load is approximately 50%of the ultimate pullout load.The anchors designed to test failure mode C were installed with an endplate and had a higher toughness than the straight bar anchors.The shear stress on the grout-rock interface is the largest at the endplate and attenuates upward before slip starts along the interface.When the ultimate pullout load is reached,and the grout column starts to slip,the shear stress is approximately constant.The bond shear strength on the anchor-grout interface was approximately 20%of the uniaxial compressive strength of the grout,and the bond strength of the grout-rock interface was around 5%for that of the grout.The grout-rock interface is likely determined by whichever is weaker,the grout or the rock. 展开更多
关键词 Rock anchor Load transfer Shear stress distribution Bond shear strength Field test
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