In recent years,the development and research of electrochemical energy storage systems that can efficiently transform chemical energy into electrical energy with a long service life have become a key area of study.Sod...In recent years,the development and research of electrochemical energy storage systems that can efficiently transform chemical energy into electrical energy with a long service life have become a key area of study.Sodium-ion batteries,leveraging their chemical similarity to lithium-ion batteries,along with their abundant resources and low cost,are seen as a viable alternative to lithium-ion batteries.Additionally,all-solid-state sodium-ion batteries have drawn significant attention due to safety considerations.Among the solid electrolytes for all-solid-state sodium-ion batteries,the NASICON solid-state electrolyte emerges as one of the most promising choices for sodium battery solid electrolytes.However,to date,there has not been a comprehensive review summarizing the existing problems of NASICON electrolyte materials and the corresponding specific modification methods.This review simply summarizes the present issues of NASICON for all-solid-state sodium-ion batteries,such as,the low ionic conductivity,the poor interface stability and compatibility,and the dendrite formation.Then,the corresponding solutions to address these issues are discussed,including the ion doping,the interface modification,the sintering parameters optimization,and the composite electrolytes regulation.Finally,the perspectives of NASICON solid-state electrolyte are discussed.展开更多
A simplified mechanical model of ultra-high pillar was established and its potential energy expression was derived under axial load on the basis of energy theory. Under critical conditions according to the nonlinear t...A simplified mechanical model of ultra-high pillar was established and its potential energy expression was derived under axial load on the basis of energy theory. Under critical conditions according to the nonlinear theory, the critical behaviors and the forming mechanism of pillar instability were discussed by external disturbance , such as stresses waves by blasting , axial force eccentricity ratherish and imperfections in pillar. The results show that the micro-disturbances attenuate with time and they are independence each other when pillar is in the stability state. Their effects on the stability of system are inessential. The correlation degree of disturbances increases sharply and various micro-disturbances are relative and nested reciprocally when the system is in critical state and they also cooperate with each other, which induces system to reach a new state.展开更多
According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism....According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential fimction and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.展开更多
The laminated overburden model(La Model)has been widely used for pillar design and stability analysis.As a boundary element program,the La Model program is sensitive to the boundary condition,which should be considere...The laminated overburden model(La Model)has been widely used for pillar design and stability analysis.As a boundary element program,the La Model program is sensitive to the boundary condition,which should be considered before creating the model.To eliminate the boundary effect in a La Model pillar stability analysis,a suitable boundary buffer zone is needed around the model edge.The radius of influence(R)and the abutment load extent(D)are two major factors that affect the stresses and displacements calculated in LaM odel.To determine the optimum buffer zone extent,a database of case histories was analyzed using the La Model program.Values for R and D were varied until a buffer zone having negligible influence on the pillar stability factor(SF)of the active mining zone(AMZ)was determined.展开更多
In order to determine the slip plane of slope directly by the calculation results of strength reduction method, and analyze the influential factors of slope stability, a numerical model was established in plane strain...In order to determine the slip plane of slope directly by the calculation results of strength reduction method, and analyze the influential factors of slope stability, a numerical model was established in plane strain mode by FLAC3D for homogeneous soil slope, whose parameters were reduced until the slope reached the critical state. Then FISH program was used to get the location data of slip plane from displacement contour lines. Furthermore, the method to determine multiple slip planes was also proposed by setting different heights of elastic areas. The influential factors for the stability were analyzed, including cohesion, internal friction angle, and tensile strength. The calculation results show that with the increase of cohesion, failure mode of slope changes from shallow slipping to the deep slipping, while inclination of slip plane becomes slower and slipping volume becomes larger; with the increase of friction angle, failure mode of slope changes from deep slipping to shallow slipping, while slip plane becomes steeper and upper border of slip plane comes closer to the vertex of slope; the safety factor increases little and slip plane goes far away from vertex of slope with the increase of tensile strength.展开更多
Room and pillar sizes are key factors for safe mining and ore recovery in open-stope mining. To investigate the influence of room and pillar configurations on stope stability in highly fractured and weakened areas, an...Room and pillar sizes are key factors for safe mining and ore recovery in open-stope mining. To investigate the influence of room and pillar configurations on stope stability in highly fractured and weakened areas, an orthogonal design with two factors, three levels and nine runs was proposed, followed by three-dimensional numerical simulation using ANSYS and FLAC3~. Results show that surface settlement after excavation is concentrically ringed, and increases with the decrease of pillar width and distances to stope gobs. In the meantime, the ore-control fault at the ore-rock boundary and the fractured argillaceous dolomite with intercalated slate at the hanging wall deteriorate the roof settlement. Additionally, stope stability is challenged due to pillar rheological yield and stress concentration, and both are induced by redistribution of stress and plastic zones after mining. Following an objective function and a constraint function, room and pillar configuration with widths of 14 m and 16 m, respectively, is presented as the optimization for improving the ore recovery rate while maintaining a safe working environment.展开更多
Based on the upper bound limit analysis theorem and the shear strength reduction technique, the equation for expressing critical limit-equilibrium state was employed to define the safety factor of a given slope and it...Based on the upper bound limit analysis theorem and the shear strength reduction technique, the equation for expressing critical limit-equilibrium state was employed to define the safety factor of a given slope and its corresponding critical failure mechanism by means of the kinematical approach of limit analysis theory. The nonlinear shear strength parameters were treated as variable parameters and a kinematically admissible failure mechanism was considered for calculation schemes. The iterative optimization method was adopted to obtain the safety factors. Case study and comparative analysis show that solutions presented here agree with available predictions when nonlinear criterion reduces to linear criterion, and the validity of present method could be illuminated. From the numerical results, it can also be seen that nonlinear parameter rn, slope foot gradient ,β, height of slope H, slope top gradient a and soil bulk density γ have significant effects on the safety factor of the slope.展开更多
Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of e...Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of embedment depth when assessing the seismic stability of gravity retaining walls with the pattern of pure rotation. In the framework of upper bound theorem of limit analysis, pseudo-static method was applied into two groups of parallel rigid soil slices methods in order to account for the effect of embedment depth on evaluating the critical acceleration of wall-soil system. The present analytical solution is identical to the results obtained from using limit equilibrium method, and the two methods are based on different theory backgrounds. Parameter analysis indicates that the critical acceleration increases slowly when the ratio of the embedment depth to the total height of the wall is from 0 to 0.15 and increases drastically when the ratio exceeds 0.15.展开更多
基金Projects(52204378,22309209)supported by the National Natural Science Foundation of ChinaProject(2023JJ40709)supported by the Natural Science Foundation of Hunan Province,China。
文摘In recent years,the development and research of electrochemical energy storage systems that can efficiently transform chemical energy into electrical energy with a long service life have become a key area of study.Sodium-ion batteries,leveraging their chemical similarity to lithium-ion batteries,along with their abundant resources and low cost,are seen as a viable alternative to lithium-ion batteries.Additionally,all-solid-state sodium-ion batteries have drawn significant attention due to safety considerations.Among the solid electrolytes for all-solid-state sodium-ion batteries,the NASICON solid-state electrolyte emerges as one of the most promising choices for sodium battery solid electrolytes.However,to date,there has not been a comprehensive review summarizing the existing problems of NASICON electrolyte materials and the corresponding specific modification methods.This review simply summarizes the present issues of NASICON for all-solid-state sodium-ion batteries,such as,the low ionic conductivity,the poor interface stability and compatibility,and the dendrite formation.Then,the corresponding solutions to address these issues are discussed,including the ion doping,the interface modification,the sintering parameters optimization,and the composite electrolytes regulation.Finally,the perspectives of NASICON solid-state electrolyte are discussed.
文摘A simplified mechanical model of ultra-high pillar was established and its potential energy expression was derived under axial load on the basis of energy theory. Under critical conditions according to the nonlinear theory, the critical behaviors and the forming mechanism of pillar instability were discussed by external disturbance , such as stresses waves by blasting , axial force eccentricity ratherish and imperfections in pillar. The results show that the micro-disturbances attenuate with time and they are independence each other when pillar is in the stability state. Their effects on the stability of system are inessential. The correlation degree of disturbances increases sharply and various micro-disturbances are relative and nested reciprocally when the system is in critical state and they also cooperate with each other, which induces system to reach a new state.
基金Project(50578060) supported by the National Natural Science Foundation of China
文摘According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential fimction and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.
文摘The laminated overburden model(La Model)has been widely used for pillar design and stability analysis.As a boundary element program,the La Model program is sensitive to the boundary condition,which should be considered before creating the model.To eliminate the boundary effect in a La Model pillar stability analysis,a suitable boundary buffer zone is needed around the model edge.The radius of influence(R)and the abutment load extent(D)are two major factors that affect the stresses and displacements calculated in LaM odel.To determine the optimum buffer zone extent,a database of case histories was analyzed using the La Model program.Values for R and D were varied until a buffer zone having negligible influence on the pillar stability factor(SF)of the active mining zone(AMZ)was determined.
基金Project(20060533071) supported by the Doctoral Program Foundation of Higher Education of ChinaProject (20060400264) supported by China Postdoctoral Science Foundation+1 种基金Project (50774093) supported by the National Natural Science Foundation of ChinaProject (1343-74236000014) supported by Graduate Student Innovation Foundation of Hunan Province, China
文摘In order to determine the slip plane of slope directly by the calculation results of strength reduction method, and analyze the influential factors of slope stability, a numerical model was established in plane strain mode by FLAC3D for homogeneous soil slope, whose parameters were reduced until the slope reached the critical state. Then FISH program was used to get the location data of slip plane from displacement contour lines. Furthermore, the method to determine multiple slip planes was also proposed by setting different heights of elastic areas. The influential factors for the stability were analyzed, including cohesion, internal friction angle, and tensile strength. The calculation results show that with the increase of cohesion, failure mode of slope changes from shallow slipping to the deep slipping, while inclination of slip plane becomes slower and slipping volume becomes larger; with the increase of friction angle, failure mode of slope changes from deep slipping to shallow slipping, while slip plane becomes steeper and upper border of slip plane comes closer to the vertex of slope; the safety factor increases little and slip plane goes far away from vertex of slope with the increase of tensile strength.
基金Projects(50934002,51074013,51104100)supported by the National Natural Science Foundation of ChinaProject(IRT0950)supported by the Program for Changjiang Scholars and Innovative Research Team in University of China
文摘Room and pillar sizes are key factors for safe mining and ore recovery in open-stope mining. To investigate the influence of room and pillar configurations on stope stability in highly fractured and weakened areas, an orthogonal design with two factors, three levels and nine runs was proposed, followed by three-dimensional numerical simulation using ANSYS and FLAC3~. Results show that surface settlement after excavation is concentrically ringed, and increases with the decrease of pillar width and distances to stope gobs. In the meantime, the ore-control fault at the ore-rock boundary and the fractured argillaceous dolomite with intercalated slate at the hanging wall deteriorate the roof settlement. Additionally, stope stability is challenged due to pillar rheological yield and stress concentration, and both are induced by redistribution of stress and plastic zones after mining. Following an objective function and a constraint function, room and pillar configuration with widths of 14 m and 16 m, respectively, is presented as the optimization for improving the ore recovery rate while maintaining a safe working environment.
基金Project(2006318802111) supported by West Traffic Construction Science and Technology of ChinaProject(2008yb004) supported by Excellent Doctorate Dissertations of Central South University, China Project(2008G032-3) supported by Key Item of Science and Technology Research of Railway Ministry of China
文摘Based on the upper bound limit analysis theorem and the shear strength reduction technique, the equation for expressing critical limit-equilibrium state was employed to define the safety factor of a given slope and its corresponding critical failure mechanism by means of the kinematical approach of limit analysis theory. The nonlinear shear strength parameters were treated as variable parameters and a kinematically admissible failure mechanism was considered for calculation schemes. The iterative optimization method was adopted to obtain the safety factors. Case study and comparative analysis show that solutions presented here agree with available predictions when nonlinear criterion reduces to linear criterion, and the validity of present method could be illuminated. From the numerical results, it can also be seen that nonlinear parameter rn, slope foot gradient ,β, height of slope H, slope top gradient a and soil bulk density γ have significant effects on the safety factor of the slope.
基金Project(41472245)supported by the National Natural Science Foundation of ChinaProject(CQGT-KJ-2014049)supported by the Chongqing Administration of Land,Resources and Housing,ChinaProject(106112014CDJZR200009)supported by the Fundamental Research Funds for the Central Universities,China
文摘Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of embedment depth when assessing the seismic stability of gravity retaining walls with the pattern of pure rotation. In the framework of upper bound theorem of limit analysis, pseudo-static method was applied into two groups of parallel rigid soil slices methods in order to account for the effect of embedment depth on evaluating the critical acceleration of wall-soil system. The present analytical solution is identical to the results obtained from using limit equilibrium method, and the two methods are based on different theory backgrounds. Parameter analysis indicates that the critical acceleration increases slowly when the ratio of the embedment depth to the total height of the wall is from 0 to 0.15 and increases drastically when the ratio exceeds 0.15.
