The construction of the tunnel face is a critical aspect of tunnel excavation,and its supporting equipment mainly includes drilling jumbos,arch installation trolleys,wet spraying manipulators,and anchor bolt trolleys....The construction of the tunnel face is a critical aspect of tunnel excavation,and its supporting equipment mainly includes drilling jumbos,arch installation trolleys,wet spraying manipulators,and anchor bolt trolleys.To address the issues of high construction costs and the need to replace equipment for different processes,this paper designs an economical and practical multi-functional integrated trolley based on engineering cases.This trolley is suitable for various construction methods such as full-face excavation and benching method,and integrates functions such as drilling and blasting holes,anchor bolt holes,advance grouting holes,pipe roof construction,charging,anchor bolt installation and grouting,and arch mesh installation.It reduces the number of operators,improves the tunnel working environment,lowers construction costs,and enhances construction efficiency.展开更多
Extracorporeal liver surgery(ELS), also known as liver autotransplantation, is a hybrid(cross-fertilized) surgery incorporating the technical knowledge from extreme liver and transplant liver surgeries, and recently b...Extracorporeal liver surgery(ELS), also known as liver autotransplantation, is a hybrid(cross-fertilized) surgery incorporating the technical knowledge from extreme liver and transplant liver surgeries, and recently became more embraced and popularized among leading centers. ELS could be summarized into three major categories, namely, ex-situ liver resection and autotransplantation(ELRA), ante-situm liver resection and autotransplantation(ALRA) and auxiliary partial liver autotransplantation(APLA). The successful development of ELS during the past 37 years is definitely inseparable from continuous effort s done by Chinese surgeons and researchers. Especially, the precision liver surgery paradigm has allowed to transform ELS into a modularized, more simplified, and standardized surgery, to upgrade surgical skills, to improve peri-operative outcome and long-term survival, to increase the capability of surgeons to select more complex diseases and to expand the level of medical service to the population. This review highlights the Chinese contributions to the field of ELS, focusing thereby on features of different surgical types, technical innovations, disease selection and surgical indication, patient prognosis and future perspectives.展开更多
The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importa...The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importance in China’s space exploration endeavors.Among these,MSS-1A is the world’s first high-precision scientific satellite dedicated to exploring the geomagnetic field and space environment at low latitudes.Equipped with two high-precision vector magnetometers and one scalar magnetometer,which are integrally installed on a highly stable nonmagnetic optical bench,the MSS-1A enables simultaneous high-precision measurements of both the Earth’s vector magnetic field and its scalar components.Its design integrates several state-of-the-art technologies,including arc-second-level thermal stability control,nonmagnetic thermal control for the optical bench,and ultra-high magnetic cleanliness control.These innovations effectively minimize magnetic interference originating from the satellite itself,thereby substantially improving the precision of geomagnetic field measurements and establishing a robust technical foundation for future magnetic survey satellite constellations.展开更多
With the rapid development of high-speed railway tunnel construction mileage and technology,the construction of the tunnel face is a key part of tunnel construction in high-speed railway tunnel projects.As mechanizati...With the rapid development of high-speed railway tunnel construction mileage and technology,the construction of the tunnel face is a key part of tunnel construction in high-speed railway tunnel projects.As mechanization and intelligence levels continue to increase,supporting equipment mainly includes rock drilling trolleys,arch installation trolleys,wet spraying robots,anchor trolleys,etc.To address the issues of high construction costs and the need to replace equipment for different processes,this paper designs an economical and practical multi-functional integrated trolley for high-speed railway double-track tunnels based on engineering cases.This trolley can adapt to various tunnel face excavation methods such as the full-face method and the bench method,enabling integrated functions such as drilling and blasting holes,anchor holes,advance grouting holes,pipe roof construction,charging,anchor installation and grouting,and arch mesh installation.This reduces the number of operators,improves the working environment of high-speed railway tunnels,lowers construction costs,and enhances construction efficiency.展开更多
The dynamic model of the ball screw mechanism(BSM)in spatial motion,developed in Part I of the study titled‘research and experimental analysis on precision degradation of BSM at low speed’,has been validated through...The dynamic model of the ball screw mechanism(BSM)in spatial motion,developed in Part I of the study titled‘research and experimental analysis on precision degradation of BSM at low speed’,has been validated through a comparison between calculated values and experimentally measured data obtained from a comprehensive ball-screw test bench.In order to study the perform-ance parameters related to the precision degradation characteristics of ball screw under different pre-loads and speeds,the precision degradation test bench for ball screw is set up.Through the experi-ment on the ball-screw comprehensive test bench,the drag torque,stroke deviation,acceleration peak value,axial contact stiffness and other parameters of the BSM under different speeds are ob-tained,and the different preloads are obtained by the drag torque,the changing regularity of which is consistent with the simulation results.A comprehensive analysis of the experimental data reveals that the dynamic characteristics of the ball screw’s spatial motion are significantly influenced by gy-roscopic torque effects.By incorporating these parametric effects,the accuracy degradation charac-teristics of ball screw under different preloads and speeds can be well analyzed.This methodology establishes a technical foundation for investigating ball screw accuracy retention characteristics.展开更多
For strapdown stabilized platform used in automatic vertical drilling system,a new dynamic measurement algorithm based on three-axis accelerometer and three-axis fluxgate measurement signals is proposed and simulated ...For strapdown stabilized platform used in automatic vertical drilling system,a new dynamic measurement algorithm based on three-axis accelerometer and three-axis fluxgate measurement signals is proposed and simulated under the condition of small inclination dynamic rotation.The error compensation algorithm is also proposed.The bench test of strapdown stabilized platform is designed and carried out.The results show that:When the azimuth angle is the same,the larger the inclination angle is,the greater the error of the measurement results will be.When the inclination angle is the same,the measurement error is the largest when the azimuth angle is 90°and 270°,and the measurement error curve presents a sinusoidal change with the change of azimuth angle.After the error function compensation,the error curve between the calculation results and the true value is basically not affected by the inclination angle and the azimuth angle,and the calculation accuracy is signifi cantly improved.Under the random rotating speed of 0-180 rpm,the minimum error of the measured well inclination value was no more than 0.03°and the maximum was no more than 1.58°.The feasibility of the proposed dynamic azimuth measurement algorithm is verifi ed.This article provides a technical reference for the strapdown automatic drilling system.展开更多
Reflecting on 16 years of continuous evolution at the World Journal of Stem Cells,this editorial offers a forward-looking vision for redefining the framework of scientific publishing.With the emergence of artificial i...Reflecting on 16 years of continuous evolution at the World Journal of Stem Cells,this editorial offers a forward-looking vision for redefining the framework of scientific publishing.With the emergence of artificial intelligence,open science,and the growing need for translational value,we propose shifting from traditional citation-based assessments toward an impact and progress framework,anchored by the Economic Impact Factor.The World Journal of Stem Cells experience,grounded in metrics and milestones,supports this evolution:Among the more than 1200 published articles since inception,our top 10 cited works have collectively accrued over 2475 citations,led by Kyurkchiev et al(398 citations)and Casteilla et al(392 citations).Emerging scholars such as Ann De Becker and Nipha Chaicharoenaudomrung have shaped the next generation of research,as seen in our top 10 junior authors table.Clinically,World Journal of Stem Cells has supported critical translational work,such as Tsang et al’s mesenchymal stem cell stroke trial(27 citations),illustrating real-world impact.Thematic breadth remains a cornerstone,with 22 focus areas including artificial intelligence-integrated programming,spatial single-cell biology,CRISPR-based gene editing,and bench-to-bedside translation.As Nature and other leading publishers move toward transparent peer review,World Journal of Stem Cells embraces editorial co-creation,recognizing peer reviewers and editors as contributors with“10000-foot eagle views”by publishing peer-review reports side-by-side with the related manuscripts since its inception.Together,these shifts signify a call to recalibrate what we value in science-not just what is cited,but what truly counts.展开更多
In the construction of shallow-buried concealed tunnels,the control of surrounding rock stability is a core challenge,which is crucial to construction safety and structural performance.A two-dimensional model was esta...In the construction of shallow-buried concealed tunnels,the control of surrounding rock stability is a core challenge,which is crucial to construction safety and structural performance.A two-dimensional model was established using Midas GTS NX,combined with bench cut method excavation simulation.The laws of vault and surface settlement were quantitatively analyzed through displacement nephograms,and the spatiotemporal characteristics of surrounding rock displacement were revealed.The results show that under the established excavation and support measures,the displacement and settlement meet the specification requirements.Meanwhile,the Analytic Hierarchy Process(AHP)was introduced to determine weights and analyze the coupling correlation of factors through judgment matrices,clarifying the influence degrees of surrounding rock grade,support strength,and other factors to achieve multi-dimensional evaluation.Furthermore,the Fuzzy Comprehensive Evaluation method was integrated to quantify the mapping relationship between surrounding rock stability and safety,and the safety grade was obtained.Finally,measures such as strengthening support,optimizing excavation parameters,refined exploration,and improving management were proposed to enhance surrounding rock stability and reduce construction risks.展开更多
This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubat...This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time.展开更多
转化医学（translational medicine）,也称转化研究（translational research）,是医学领域的新概念[1—2],强调把生物基础研究的最新成果快速有效地转化为临床医学技术的过程,即从实验室到病床（bench to bedside）再从病床到实验室（b...转化医学（translational medicine）,也称转化研究（translational research）,是医学领域的新概念[1—2],强调把生物基础研究的最新成果快速有效地转化为临床医学技术的过程,即从实验室到病床（bench to bedside）再从病床到实验室（bedside to bench）的双向连续过程,简称为“B-to-B或B2B”。康复医学是有别于临床医学的以“功能障碍”患者为服务对象的学科[3]。展开更多
针对一种硬质烟用滤棒的复合添加需求,设计一种烟用滤棒上下料机构。采用瞬态动力学分析方法,运用ANSYS Work Bench软件对滤棒上下料机构进行瞬态动力学仿真,并从结构动力学角度对该机构进行动态特性研究。分析结果显示,滤棒上下料机构...针对一种硬质烟用滤棒的复合添加需求,设计一种烟用滤棒上下料机构。采用瞬态动力学分析方法,运用ANSYS Work Bench软件对滤棒上下料机构进行瞬态动力学仿真,并从结构动力学角度对该机构进行动态特性研究。分析结果显示,滤棒上下料机构的最大等效应力112.54 MPa,小于材料的许用应力。通过搭建实验平台进行试验,验证该滤棒上下料机构的合理性及稳定性。研究结果表明:滤棒上下料机构结构设计合理,取料成功率达到100%,能够满足工作要求。展开更多
The paper reviews the development of prediction formulas for the fragmentation from bench blasting.Much attention has been paid to the Kuz-Ram model,its development and errors,and the mean vs.median misunderstanding.T...The paper reviews the development of prediction formulas for the fragmentation from bench blasting.Much attention has been paid to the Kuz-Ram model,its development and errors,and the mean vs.median misunderstanding.The work by the US Bureau of Mines(USBM)and Chung and Katsabanis are also reviewed,as well as the two Julius Kruttschnitt Mineral Research Centre(JKMRC)models,i.e.the crush zone model(CZM)and the two-component model(TCM),which were developed to cope with the underestimation of blasting fines.The change brought by the Swebrec distribution and the associated Kuznetsov-Cunningham-Ouchterlony(KCO)model is described.Studying distribution-free fragment sizes xP for an arbitrary mass passing P led to the discovery of the fragmentation-energy fan,and with the help of dimensional analysis,to the new fragmentation prediction model xP-frag,which has much lower errors than those of the Kuz-Ram and CZM models.展开更多
A precondition for correctly analyzing the stability of a slope and designing its bracing structure is to study and determine the influence of excavation blasting on the properties of weak intercalation in the layered...A precondition for correctly analyzing the stability of a slope and designing its bracing structure is to study and determine the influence of excavation blasting on the properties of weak intercalation in the layered rock slope. On the basis of in-situ stratification-cracking blasting tests, the properties of weak intercalation were investigated using the LS-DYNA3D program. The displacement distribution and compactness of weak intercalation at different positions away from the charge center and their various laws are discussed. The critical displacement of stratification-cracking （0.1 mm） was obtained, and an approximate expression of compactness were deduced. Furthermore, through the simulation of a layered rock blasting under the same geological conditions, the stratification-cracking effect of deep-hole blasting on the properties of weak intercalation was compared with that of short-hole blasting, and the influencing differences, in addition to their causes, were analyzed. The results indicated that the blasting cavity of weak intercalation in short-hole blasting with a radius of 40 mm was nearly a circle, whose radius was about 28.7 cm; whereas in deep-hole blasting with a radius of 150 mm, the shape of the blasting cavity was different from that in short-hole blasting, the radius of the cavity behind the charge （89.1 cm） was further smaller than those of the other three （138.7 cm）, and there were sharp crinkles on the surface of weak intercalation. When the distance from the charge center （DCC） was less than 40 and 150 cm in short-hole and deep-hole blasting, respectively, the displacement of weak intercalation was reduced remarkably with the increase in DCC.展开更多
文摘The construction of the tunnel face is a critical aspect of tunnel excavation,and its supporting equipment mainly includes drilling jumbos,arch installation trolleys,wet spraying manipulators,and anchor bolt trolleys.To address the issues of high construction costs and the need to replace equipment for different processes,this paper designs an economical and practical multi-functional integrated trolley based on engineering cases.This trolley is suitable for various construction methods such as full-face excavation and benching method,and integrates functions such as drilling and blasting holes,anchor bolt holes,advance grouting holes,pipe roof construction,charging,anchor bolt installation and grouting,and arch mesh installation.It reduces the number of operators,improves the tunnel working environment,lowers construction costs,and enhances construction efficiency.
基金supported by grants from the Beijing Hospitals Authority Youth Program (12022B4010)BTCH Young Talent En-lightenment Program (2024QMRC24)CAMS Innovation Fund for Medical Sciences (2019-I2M-5–056)。
文摘Extracorporeal liver surgery(ELS), also known as liver autotransplantation, is a hybrid(cross-fertilized) surgery incorporating the technical knowledge from extreme liver and transplant liver surgeries, and recently became more embraced and popularized among leading centers. ELS could be summarized into three major categories, namely, ex-situ liver resection and autotransplantation(ELRA), ante-situm liver resection and autotransplantation(ALRA) and auxiliary partial liver autotransplantation(APLA). The successful development of ELS during the past 37 years is definitely inseparable from continuous effort s done by Chinese surgeons and researchers. Especially, the precision liver surgery paradigm has allowed to transform ELS into a modularized, more simplified, and standardized surgery, to upgrade surgical skills, to improve peri-operative outcome and long-term survival, to increase the capability of surgeons to select more complex diseases and to expand the level of medical service to the population. This review highlights the Chinese contributions to the field of ELS, focusing thereby on features of different surgical types, technical innovations, disease selection and surgical indication, patient prognosis and future perspectives.
文摘The Macao Science Satellite-1(MSS-1)is the first space science satellite jointly developed on the Chinese mainland and in Macao region.It comprises two satellites,named MSS-1A and MSS-1B,and holds considerable importance in China’s space exploration endeavors.Among these,MSS-1A is the world’s first high-precision scientific satellite dedicated to exploring the geomagnetic field and space environment at low latitudes.Equipped with two high-precision vector magnetometers and one scalar magnetometer,which are integrally installed on a highly stable nonmagnetic optical bench,the MSS-1A enables simultaneous high-precision measurements of both the Earth’s vector magnetic field and its scalar components.Its design integrates several state-of-the-art technologies,including arc-second-level thermal stability control,nonmagnetic thermal control for the optical bench,and ultra-high magnetic cleanliness control.These innovations effectively minimize magnetic interference originating from the satellite itself,thereby substantially improving the precision of geomagnetic field measurements and establishing a robust technical foundation for future magnetic survey satellite constellations.
文摘With the rapid development of high-speed railway tunnel construction mileage and technology,the construction of the tunnel face is a key part of tunnel construction in high-speed railway tunnel projects.As mechanization and intelligence levels continue to increase,supporting equipment mainly includes rock drilling trolleys,arch installation trolleys,wet spraying robots,anchor trolleys,etc.To address the issues of high construction costs and the need to replace equipment for different processes,this paper designs an economical and practical multi-functional integrated trolley for high-speed railway double-track tunnels based on engineering cases.This trolley can adapt to various tunnel face excavation methods such as the full-face method and the bench method,enabling integrated functions such as drilling and blasting holes,anchor holes,advance grouting holes,pipe roof construction,charging,anchor installation and grouting,and arch mesh installation.This reduces the number of operators,improves the working environment of high-speed railway tunnels,lowers construction costs,and enhances construction efficiency.
基金Supported by the National Natural Science Foundation of China(No.51575014,51505020)the Key Foundation Project of China Academy of Railway Sciences(No.2021YJ200).
文摘The dynamic model of the ball screw mechanism(BSM)in spatial motion,developed in Part I of the study titled‘research and experimental analysis on precision degradation of BSM at low speed’,has been validated through a comparison between calculated values and experimentally measured data obtained from a comprehensive ball-screw test bench.In order to study the perform-ance parameters related to the precision degradation characteristics of ball screw under different pre-loads and speeds,the precision degradation test bench for ball screw is set up.Through the experi-ment on the ball-screw comprehensive test bench,the drag torque,stroke deviation,acceleration peak value,axial contact stiffness and other parameters of the BSM under different speeds are ob-tained,and the different preloads are obtained by the drag torque,the changing regularity of which is consistent with the simulation results.A comprehensive analysis of the experimental data reveals that the dynamic characteristics of the ball screw’s spatial motion are significantly influenced by gy-roscopic torque effects.By incorporating these parametric effects,the accuracy degradation charac-teristics of ball screw under different preloads and speeds can be well analyzed.This methodology establishes a technical foundation for investigating ball screw accuracy retention characteristics.
基金The financial supports from National key plan project for research and development of China (2019YFA0708300) and (2023YFC3009200)。
文摘For strapdown stabilized platform used in automatic vertical drilling system,a new dynamic measurement algorithm based on three-axis accelerometer and three-axis fluxgate measurement signals is proposed and simulated under the condition of small inclination dynamic rotation.The error compensation algorithm is also proposed.The bench test of strapdown stabilized platform is designed and carried out.The results show that:When the azimuth angle is the same,the larger the inclination angle is,the greater the error of the measurement results will be.When the inclination angle is the same,the measurement error is the largest when the azimuth angle is 90°and 270°,and the measurement error curve presents a sinusoidal change with the change of azimuth angle.After the error function compensation,the error curve between the calculation results and the true value is basically not affected by the inclination angle and the azimuth angle,and the calculation accuracy is signifi cantly improved.Under the random rotating speed of 0-180 rpm,the minimum error of the measured well inclination value was no more than 0.03°and the maximum was no more than 1.58°.The feasibility of the proposed dynamic azimuth measurement algorithm is verifi ed.This article provides a technical reference for the strapdown automatic drilling system.
文摘Reflecting on 16 years of continuous evolution at the World Journal of Stem Cells,this editorial offers a forward-looking vision for redefining the framework of scientific publishing.With the emergence of artificial intelligence,open science,and the growing need for translational value,we propose shifting from traditional citation-based assessments toward an impact and progress framework,anchored by the Economic Impact Factor.The World Journal of Stem Cells experience,grounded in metrics and milestones,supports this evolution:Among the more than 1200 published articles since inception,our top 10 cited works have collectively accrued over 2475 citations,led by Kyurkchiev et al(398 citations)and Casteilla et al(392 citations).Emerging scholars such as Ann De Becker and Nipha Chaicharoenaudomrung have shaped the next generation of research,as seen in our top 10 junior authors table.Clinically,World Journal of Stem Cells has supported critical translational work,such as Tsang et al’s mesenchymal stem cell stroke trial(27 citations),illustrating real-world impact.Thematic breadth remains a cornerstone,with 22 focus areas including artificial intelligence-integrated programming,spatial single-cell biology,CRISPR-based gene editing,and bench-to-bedside translation.As Nature and other leading publishers move toward transparent peer review,World Journal of Stem Cells embraces editorial co-creation,recognizing peer reviewers and editors as contributors with“10000-foot eagle views”by publishing peer-review reports side-by-side with the related manuscripts since its inception.Together,these shifts signify a call to recalibrate what we value in science-not just what is cited,but what truly counts.
文摘In the construction of shallow-buried concealed tunnels,the control of surrounding rock stability is a core challenge,which is crucial to construction safety and structural performance.A two-dimensional model was established using Midas GTS NX,combined with bench cut method excavation simulation.The laws of vault and surface settlement were quantitatively analyzed through displacement nephograms,and the spatiotemporal characteristics of surrounding rock displacement were revealed.The results show that under the established excavation and support measures,the displacement and settlement meet the specification requirements.Meanwhile,the Analytic Hierarchy Process(AHP)was introduced to determine weights and analyze the coupling correlation of factors through judgment matrices,clarifying the influence degrees of surrounding rock grade,support strength,and other factors to achieve multi-dimensional evaluation.Furthermore,the Fuzzy Comprehensive Evaluation method was integrated to quantify the mapping relationship between surrounding rock stability and safety,and the safety grade was obtained.Finally,measures such as strengthening support,optimizing excavation parameters,refined exploration,and improving management were proposed to enhance surrounding rock stability and reduce construction risks.
文摘This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time.
文摘转化医学（translational medicine）,也称转化研究（translational research）,是医学领域的新概念[1—2],强调把生物基础研究的最新成果快速有效地转化为临床医学技术的过程,即从实验室到病床（bench to bedside）再从病床到实验室（bedside to bench）的双向连续过程,简称为“B-to-B或B2B”。康复医学是有别于临床医学的以“功能障碍”患者为服务对象的学科[3]。
文摘针对一种硬质烟用滤棒的复合添加需求,设计一种烟用滤棒上下料机构。采用瞬态动力学分析方法,运用ANSYS Work Bench软件对滤棒上下料机构进行瞬态动力学仿真,并从结构动力学角度对该机构进行动态特性研究。分析结果显示,滤棒上下料机构的最大等效应力112.54 MPa,小于材料的许用应力。通过搭建实验平台进行试验,验证该滤棒上下料机构的合理性及稳定性。研究结果表明:滤棒上下料机构结构设计合理,取料成功率达到100%,能够满足工作要求。
基金provided by MULUniversidad Politecnica de Madrid
文摘The paper reviews the development of prediction formulas for the fragmentation from bench blasting.Much attention has been paid to the Kuz-Ram model,its development and errors,and the mean vs.median misunderstanding.The work by the US Bureau of Mines(USBM)and Chung and Katsabanis are also reviewed,as well as the two Julius Kruttschnitt Mineral Research Centre(JKMRC)models,i.e.the crush zone model(CZM)and the two-component model(TCM),which were developed to cope with the underestimation of blasting fines.The change brought by the Swebrec distribution and the associated Kuznetsov-Cunningham-Ouchterlony(KCO)model is described.Studying distribution-free fragment sizes xP for an arbitrary mass passing P led to the discovery of the fragmentation-energy fan,and with the help of dimensional analysis,to the new fragmentation prediction model xP-frag,which has much lower errors than those of the Kuz-Ram and CZM models.
基金supported by the National Natural Science Foundation of China (No.50574076 and No.50838006)
文摘A precondition for correctly analyzing the stability of a slope and designing its bracing structure is to study and determine the influence of excavation blasting on the properties of weak intercalation in the layered rock slope. On the basis of in-situ stratification-cracking blasting tests, the properties of weak intercalation were investigated using the LS-DYNA3D program. The displacement distribution and compactness of weak intercalation at different positions away from the charge center and their various laws are discussed. The critical displacement of stratification-cracking （0.1 mm） was obtained, and an approximate expression of compactness were deduced. Furthermore, through the simulation of a layered rock blasting under the same geological conditions, the stratification-cracking effect of deep-hole blasting on the properties of weak intercalation was compared with that of short-hole blasting, and the influencing differences, in addition to their causes, were analyzed. The results indicated that the blasting cavity of weak intercalation in short-hole blasting with a radius of 40 mm was nearly a circle, whose radius was about 28.7 cm; whereas in deep-hole blasting with a radius of 150 mm, the shape of the blasting cavity was different from that in short-hole blasting, the radius of the cavity behind the charge （89.1 cm） was further smaller than those of the other three （138.7 cm）, and there were sharp crinkles on the surface of weak intercalation. When the distance from the charge center （DCC） was less than 40 and 150 cm in short-hole and deep-hole blasting, respectively, the displacement of weak intercalation was reduced remarkably with the increase in DCC.
