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Mechanism of high-preload support based on the NPR anchor cable in layered soft rock tunnels
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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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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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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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Mechanical responses of anchoring structure under triaxial cyclic loading
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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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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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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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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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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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Animal experimental study on magnetic anchor technique-assisted endoscopic submucosal dissection of early gastric cancer 被引量:1
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作者 Min Pan Miao-Miao Zhang +2 位作者 Lin Zhao Yi Lyu Xiao-Peng Yan 《World Journal of Gastrointestinal Endoscopy》 2023年第11期658-665,共8页
BACKGROUND Gastric cancer(GC)has high morbidity and mortality.Moreover,because GC has no typical symptoms in the early stages,most cases are already in the advanced stages by the time the symptoms appear,thus resultin... BACKGROUND Gastric cancer(GC)has high morbidity and mortality.Moreover,because GC has no typical symptoms in the early stages,most cases are already in the advanced stages by the time the symptoms appear,thus resulting in poor prognosis and a low survival rate.Endoscopic submucosal dissection(ESD)can realize the early detection and diagnosis of GC and become the main surgical method for early GC.However,ESD has a steep learning curve and high technical skill requirements for endoscopists,which is not conducive to its widespread implementation and advancement.Therefore,a series of auxiliary techniques have been derived.AIM To evaluate the safety and efficacy of magnetic anchor technique(MAT)-assisted ESD in early GC.METHODS This was an ex vivo animal experiment.The experimental models were the isolated stomachs of pigs,which were divided into two groups,namely the study group(n=6)with MAT-assisted ESD and the control group(n=6)with traditional ESD.Comparing the total surgical time,incidence of surgical complications,complete mucosal resection rate,specimen size,and the scores of endoscopist’s satisfaction with the procedure reflected their feelings about convenience during the surgical procedure between the two groups.The magnetic anchor device for auxiliary ESD in the study group comprised three parts,an anchor magnet(AM),a target magnet(TM),and a soft tissue clip.Under gastroscopic guidance,the soft tissue clip and the TM were delivered to the pre-marked mucosal lesion through the gastroscopic operating hole.The soft tissue clip and the TM were connected by a thin wire through the TM tail structure.The soft tissue clip was released by manipulating the operating handle of the soft tissue clip in a way that the soft tissue clip and the TM were fixed to the lesion mucosa.In vitro,ESD is aided by maneuvering the AM such that the mucosal dissection surface is exposed.RESULTS The total surgical time was shorter in the study group than in the control group(26.57±0.19 vs 29.97±0.28,P<0.001),and the scores of endoscopist’s satisfaction with the procedure were higher in the study group than in the control group(9.53±0.10 vs 8.00±0.22,P<0.001).During the operation in the study group,there was no detachment of the soft tissue clip and TM and no mucosal tearing.The magnetic force between the AM and TM provided good mucosal exposure and sufficient tissue tension for ESD.The mucosal lesion was completely peeled off,and the operation was successful.There were no significant differences in the incidence of surgical complications(100%vs 83.3%),complete mucosal resection rate(100%vs 66.7%,P=0.439),and specimen size(2.44±0.04 cm vs 2.49±0.02,P=0.328)between the two groups.CONCLUSION MAT-ESD is safe and effective for early GC.It provides a preliminary basis for subsequent internal animal experiments and clinical research. 展开更多
关键词 Endoscopic submucosal dissection Gastric cancer Digestive disease Magnetic anchor technique Magnetic surgery Magnetic anchor device
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Magnetic anchor technique assisted endoscopic submucosal dissection for early esophageal cancer
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作者 Min Pan Miao-Miao Zhang +2 位作者 Shu-Qin Xu Yi Lyu Xiao-Peng Yan 《World Journal of Gastrointestinal Endoscopy》 2023年第10期584-592,共9页
BACKGROUND Esophageal cancer has high incidence globally and is often diagnosed at an advanced stage.With the widespread application of endoscopic technologies,the need for early detection and diagnosis of esophageal ... BACKGROUND Esophageal cancer has high incidence globally and is often diagnosed at an advanced stage.With the widespread application of endoscopic technologies,the need for early detection and diagnosis of esophageal cancer has gradually been realized.Endoscopic submucosal dissection(ESD)has become the standard of care for managing early tumors of the esophagus,stomach,and colon.However,due to the steep learning curve,difficult operation,and technically demanding nature of the procedure,ESD has currently been committed to the development of various assistive technologies.AIM To explore the feasibility and applicability of magnetic anchor technique(MAT)-assisted ESD for early esophageal cancer.METHODS Isolated pig esophagi were used as the experimental model,and the magnetic anchor device was designed by us.The esophagi used were divided into two groups,namely the operational and control groups,and 10 endoscopists completed the procedure.The two groups were evaluated for the following aspects:The total operative time,perforation rate,rate of whole mucosal resection,diameter of the peering mucosa,and scores of endoscopists’feelings with the procedure,including the convenience,mucosal surface exposure degree,and tissue tension.In addition,in the operational group,the soft tissue clip and the target magnet(TM)were connected by a thin wire through a small hole at the tail end of the TM.Under gastroscopic guidance,the soft tissue clip was clamped to the edge of the lesioned mucosa,which was marked in advance.By changing the position of the anchor magnet(AM)outside the esophagus,the pulling force and pulling direction of the TM could be changed,thus exposing the mucosal peeling surface and assisting the ESD.RESULTS Herein,each of the two groups comprised 10 isolated esophageal putative mucosal lesions.The diameter of the peering mucosa did not significantly differ between the two groups(2.13±0.06 vs 2.15±0.06,P=0.882).The total operative time was shorter in the operational group than in the control group(17.04±0.22 min vs 21.94±0.23 min,P<0.001).During the entire experiment,the TM remained firmly connected with the soft tissue clip and did not affect the opening,closing,and release of the soft tissue clip.The interaction between the TM and AM could provide sufficient tissue tension and completely expose the mucosa,which greatly assists the surgeon with the operation.There was no avulsion of the mucosa,and mucosal lesions were intact when peeled.Therefore,the scores of endoscopists’feelings were higher in the operational group than in the control group in terms of the convenience(9.22±0.19 vs 8.34±0.15,P=0.002),mucosal surface exposure degree(9.11±0.15 vs 8.25±0.12,P<0.001),and tissue tension(9.35±0.13 vs 8.02±0.17,P<0.001).The two groups did not significantly differ in the perforation rate and rate of whole mucosal resection.CONCLUSION We found MAT-assisted ESD safe and feasible for early esophageal cancer.It could greatly improve the endoscopic operation experience and showed good clinical application prospects. 展开更多
关键词 Magnetic surgery Magnetic anchor technique Magnetic anchor device Endoscopic submucosal dissection Early esophageal cancer
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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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Recent Study of Drag Embedment Plate Anchors in China 被引量:7
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作者 Haixiao Liu 《Journal of Marine Science and Application》 2012年第4期393-401,共9页
Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study o... Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study of drag anchors. The techniques for measuring the trajectory and movement direction of drag anchors in soils, the techniques for measuring the moving embedment point and reverse eatenary shape of the embedded drag line, the penetration mechanism and kinematic behavior of drag anchors, the ultimate embedment depth of drag anchors, the movement direction of the anchor with an arbitrary fluke section, the reverse catenary properties of the embedded drag line, the interaetional properties between drag anchor and installation line, the kinematic model of drag anchors in seabed soils, and the analytical method for predicting the anchor trajectory in soils will all be examined. The present work remarkably reduces the uncertainties in design and analysis of drag embedment plate anchors, and is beneficial to improving the application of this new type of drag anchor in offshore engineering. 展开更多
关键词 drag embedment plate anchor vertically loaded plate anchor VLA drag-in plate anchor drag anchor ultimate embedment depth movement direction kinematic model penetration mechanism kinematic behavior
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Struts框架技术简析 被引量:2
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作者 王刚 《长春师范大学学报(人文社会科学版)》 2012年第9期25-28,共4页
本文简要介绍了Struts框架技术及其相关内容,并着重对Struts框架的组件和Struts框架的高级特性进行了深入的探讨。
关键词 strutS框架 struts框架的组件 struts框架的高级特性
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Failure Envelopes of Single-Plate Rigid Helical Anchors for Floating Offshore Wind Turbine
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作者 CHEN Hong-zhen WANG Le +3 位作者 TIAN Ying-hui ZHANG Chun-hui SHEN Zhi-chao LIU Meng-meng 《China Ocean Engineering》 SCIE EI CSCD 2023年第6期1000-1010,共11页
Helical anchor is a kind of novel foundation for floating offshore wind turbines,which should be subjected to combined tensile loading caused by wind,wave and current.However,the research about the capacity of helical... Helical anchor is a kind of novel foundation for floating offshore wind turbines,which should be subjected to combined tensile loading caused by wind,wave and current.However,the research about the capacity of helical anchor was mainly examined under uniaxial loading and scarcely explored under combined loading.In this study,three-dimensional finite element limit analysis is adopted to assess the bearing capacities of single-plate rigid helical anchors with different ratios of helix to shaft diameter,D_(H)/D_(S) and embedment ratios L/D_(S).Result shows that the vertical,horizontal and moment bearing capacities increase with increasing D_(H)/D_(S) and L/D_(S).The normalized V-H failure envelopes expands with increasing L/D_(S),while the normalized V-M failure envelopes tend to contract with the increase of D_(H)/D_(S).With increasing D_(H)/D_(S) or decreasing L/D_(S),the normalized H-M failure envelopes expand when the horizontal and moment loading act in the same direction and contract when they act in the opposite direction.The effect of D_(H)/D_(S) and L/D_(S) on the shape of H-M failure envelope become insignificant when L/D_(S)≥4.A series of failure mechanisms under different loading conditions were observed and can be used to explain the trend.Besides,a series of approximate expressions were proposed to fit the uniaxial bearing capacities and the failure envelopes. 展开更多
关键词 helical anchors bearing capacity failure envelope CLAY
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Stability analysis of gravity anchor foundation of layered argillaceous sandstone under dry-wet cycles
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作者 ZHENG Jing-cheng CHEN Wei +4 位作者 ZHENG Ke-ren GU Yu-peng WANG Fei HUANG Zhen LI Yun 《Journal of Mountain Science》 SCIE CSCD 2023年第4期1118-1130,共13页
To investigate the stability of gravity anchors of suspension bridges,in-situ tests of the vertical bearing capacity of the bedrock,shear resistance of the anchor-rock interface,shear resistance of the bedrock were co... To investigate the stability of gravity anchors of suspension bridges,in-situ tests of the vertical bearing capacity of the bedrock,shear resistance of the anchor-rock interface,shear resistance of the bedrock were conducted in a suspension bridge project.Under dry-wet cycles,the deterioration law of the mechanical properties of argillaceous sandstone was identified in laboratory tests:the elastic modulus,cohesion and friction of the argillaceous sandstone deteriorated significantly at first few dry-wet cycles and then declined slowly after 10 cycles,ultimately these three mechanical parameters were reduced to about 1/3,1/3,2/3 of the initial value respectively.Moreover,numerical simulation was used to restore in-situ shear tests and a good agreement was obtained.Base on the results of in-situ and laboratory tests,the stability of the gravity anchor foundation under natural conditions and drywet cycles was calculated and its failure modes were analyzed.The results demonstrated that the dry-wet cycles caused uneven settlement of the anchor foundation,resulting in more serious stress concentration in the substrate.The dry-wet cycles remarkably reduced the stability coefficient of the anchor foundation,whose failure mode shifted from overturning failure under natural conditions to sliding failure.When there was weak interlayer in the rock layer,the anti-sliding stability of the anchor foundation was affected drastically. 展开更多
关键词 Gravity anchor foundation STABILITY In-situ tests Dry-wet cycles Numerical simulation
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Numerical simulation of rockburst disaster and control strategy of constant resistance and large deformation anchor cable in Gaoloushan tunnel
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作者 MIAO Cheng-yu JIANG Ming +6 位作者 LI Zhi-hu SUN Xiao-ming ZHANG Tong ZHANG Yong YANG Jin-kun REN Chao SONG Peng 《Journal of Mountain Science》 SCIE CSCD 2023年第6期1605-1619,共15页
The Gaoloushan Tunnel in Longnan City,Gansu Province,China,frequently experiences rockburst disasters due to high in-situ stress.Managing rockburst in deep-buried tunnels remains a challenging issue.This paper employs... The Gaoloushan Tunnel in Longnan City,Gansu Province,China,frequently experiences rockburst disasters due to high in-situ stress.Managing rockburst in deep-buried tunnels remains a challenging issue.This paper employs RFPA(Rock Failure Process Analysis)software to establish a calculation model of constant resistance and large deformation(CRLD)anchorages and analyzes the effects of different support methods and pre-stress levels on rockburst.We simulate the process of tunnel rockburst disasters and find that ordinary anchor support incurs rockburst on the right arch waist and arch top,forming a V-shaped explosion pit.CRLD anchor support has several advantages in rockburst control,such as more uniform stress distribution in the surrounding rock,a uniform distribution of plastic zones,less noticeable damage to the tunnel,and effective control of the arch top displacement.The effectiveness of the CRLD anchor support under varying pre-stress conditions shows that a higher prestress results in a smaller plastic zone of the surrounding rock and arch top displacement and a lower number of acoustic emission signals,which better explains the excavation compensation effect.Moreover,adding long anchorages in the deep surrounding rock area can better control rockburst and reduce surrounding rock deformation.Based on these findings,we propose a comprehensive control system that combines long and short anchorages and provides the optimal scheme based on calculations.Therefore,by using high-prestress CRLD anchor support and the combination of long and short anchorages at critical positions,we can enhance the integrity of the surrounding rock,effectively absorb the energy released by the surrounding rock deformation,and reduce the incidence of rockburst disasters. 展开更多
关键词 TUNNEL ROCKBURST RFPA Constant Resistance and Large Deformation anchor cable Long and short cable coupling support.
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Struts2框架核心配置文件的研究与应用 被引量:22
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作者 刘艳春 洪晓慧 《计算机技术与发展》 2013年第2期77-81,共5页
Struts2是强大的Java Web开源框架,处理过程通过配置文件完成。针对Struts2框架配置文件内容多、配置复杂、难以掌握的特点,对核心配置文件进行研究。首先,列出了Struts2框架的所有配置文件及其之间的相互关系,指出了struts.xml和struts... Struts2是强大的Java Web开源框架,处理过程通过配置文件完成。针对Struts2框架配置文件内容多、配置复杂、难以掌握的特点,对核心配置文件进行研究。首先,列出了Struts2框架的所有配置文件及其之间的相互关系,指出了struts.xml和struts.properties是核心配置文件;接着,研究struts.xml配置文件,包括struts.xml常用配置解析、struts.xml构建步骤及构建方法;最后研究struts.properties配置文件,着重研究struts.properties中包含主要的Struts2属性及配置方法。文中的研究内容,能够使开发者清晰地理解配置文件的写法与调用关系,有利于团队成员并行工作,提高开发效率。 展开更多
关键词 strutS2框架 配置文件 strutS XML strutS PROPERTIES
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基于Struts扩展框架的Web应用研究 被引量:6
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作者 刘冰 李正凡 《计算机应用》 CSCD 北大核心 2008年第10期2619-2621,2632,共4页
针对Struts框架不具备很好的视图层适应性,引入可扩展的样式语言(XSL)技术,利用XSLT强大的转换功能,把它和Struts结合在一起,对Struts的视图部分进行改进。在此基础上提出一个合理的解决方案,并给出了改进之后的模型XStruts。该模型是St... 针对Struts框架不具备很好的视图层适应性,引入可扩展的样式语言(XSL)技术,利用XSLT强大的转换功能,把它和Struts结合在一起,对Struts的视图部分进行改进。在此基础上提出一个合理的解决方案,并给出了改进之后的模型XStruts。该模型是Struts的扩展,它将表现逻辑和业务逻辑分离,支持XML、XSL等标准,具有可扩展性和易维护性,提供对多种类型客户端的支持。在提出的XStruts模型的基础上设计开发了一个典型的Web应用——网上书店系统,进一步说明XStruts模型的可行性。 展开更多
关键词 模型-视图-控制器 WEB 可扩展的样式语言 strutS Xstruts
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