This paper studies the short-term prediction methods of sectional passenger flow, and selects BP neural network combined with the characteristics of sectional passenger flow itself. With a case study, we design three ...This paper studies the short-term prediction methods of sectional passenger flow, and selects BP neural network combined with the characteristics of sectional passenger flow itself. With a case study, we design three different schemes. We use Matlab to realize the prediction of the sectional passenger flow of the Beijing subway Line 2 and make comparative analysis. The empirical research shows that combining data characteristics of sectional passenger flow with the BP neural network have good prediction accuracy.展开更多
Wind-sand flow generates erosion and deposition around obstacles such as bridges and roadbeds, resulting in sand damage and endangering railway systems in sandy regions. Previous studies have mainly focused on the flo...Wind-sand flow generates erosion and deposition around obstacles such as bridges and roadbeds, resulting in sand damage and endangering railway systems in sandy regions. Previous studies have mainly focused on the flow field around roadbeds, overlooking detailed examinations of sand particle erosion and deposition patterns near bridges and roadbeds. This study employs numerical simulations to analyze the influence of varying heights and wind speeds on sand deposition and erosion characteristics at different locations: the bridge-road transition section(side piers), middle piers, and roadbeds. The results show that the side piers, experience greater accumulation than the middle piers. Similarly, the leeward side of the roadbed witnesses more deposition compared to the windward side. Another finding reveals a reduced sand deposition length as the vertical profile, in alignment with the wind direction, moves further from the bridge abutments at the same clearance height. As wind speeds rise, there’s a decline in sand deposition and a marked increase in erosion around the side piers, middle piers and roadbeds. In conclusion, a bridge clearance that’s too low can cause intense sand damage near the side piers, while an extremely high roadbed may lead to extensive surface sand deposition. Hence, railway bridges in areas prone to sandy winds should strike a balance in clearance height. This research provides valuable guidelines for determining the most suitable bridge and roadbed heights in regions affected by wind and sand.展开更多
As the lifeline of social development,road and bridge projects are the main channel to realize resource transportation and economic circulation.Ensuring the quality of road and bridge project construction is crucial f...As the lifeline of social development,road and bridge projects are the main channel to realize resource transportation and economic circulation.Ensuring the quality of road and bridge project construction is crucial for the development of society,the economy,and people’s livelihoods.This paper studies the design of roadbed pavement structures in road and bridge transition sections.It aims to provide technical references and significance for China’s road and bridge engineering design and construction units,promoting scientific and standardized design in these actions.This will contribute to the safety and stable operation of road and bridge projects,offering effective technical support.Furthermore,it seeks to foster the sustainable and healthy development of China’s road and bridge engineering on a macro level.展开更多
In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and then processing pi...In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and then processing piles. On the basis of engineering practice, the authors analyzed the influence of foundation treatment on bridge piles in bridgehead transition section by finite-element method (FEM). This research has positive significance in predicting displacement of bridge pile, directing construction of foundation treatment, and improving quality of engineering and so forth.展开更多
In this paper,combined with the relevant speed theory and characteristics of the law,the current highway speed transition design problems are studied and analyzed.In the process of specific analysis,mainly combined wi...In this paper,combined with the relevant speed theory and characteristics of the law,the current highway speed transition design problems are studied and analyzed.In the process of specific analysis,mainly combined with the characteristics of different types of highway speed changes and road section design requirements,this paper studies and analyzes the design methods of different types of highway speed transition section.And on this basis,according to the design principles and requirements of highway operation speed transition section,the paper summarizes the matters needing attention in the design of highway operation speed transition section,in order to provide certain reference value for relevant personnel.展开更多
Firstly, sample square-circular transition tube along straight central route was modeled on CATIA software. The parameters are as follows： let the tube length is L, and the constant cross section area is S, and S = ...Firstly, sample square-circular transition tube along straight central route was modeled on CATIA software. The parameters are as follows： let the tube length is L, and the constant cross section area is S, and S = πR^2 = a2, in which R stands for the circle radius on one end, and a the square side length on the other end; set up the coordinate system with OX axis on the central route in which the origin O is on centroid of the square end and assume the cross section size at x as the square shaped with all four comers filleted in radius r which is proportional to x, that is, the linear slope of r is R/L, thus, both values r and square side length ax can be attained on the constant cross section area assumption. Secondly, some sample polygonal-circular transition tubes along straight, circular and helical central route were implemented similarly. Thirdly, numerical analysis of stress and displacement of these tubes were carried out on MSC/PATRAN software which are important to the distribution of turbulent flow and the layout of these transitional tube structures.展开更多
文摘This paper studies the short-term prediction methods of sectional passenger flow, and selects BP neural network combined with the characteristics of sectional passenger flow itself. With a case study, we design three different schemes. We use Matlab to realize the prediction of the sectional passenger flow of the Beijing subway Line 2 and make comparative analysis. The empirical research shows that combining data characteristics of sectional passenger flow with the BP neural network have good prediction accuracy.
基金financially supported by the fellowship of the China Postdoctoral Science Foundation (2021M703466)the Natural Science Foundation of Gansu Province, China (20JR10RA231)the Natural Science Foundation of Gansu Province, China (22JR5RA050)。
文摘Wind-sand flow generates erosion and deposition around obstacles such as bridges and roadbeds, resulting in sand damage and endangering railway systems in sandy regions. Previous studies have mainly focused on the flow field around roadbeds, overlooking detailed examinations of sand particle erosion and deposition patterns near bridges and roadbeds. This study employs numerical simulations to analyze the influence of varying heights and wind speeds on sand deposition and erosion characteristics at different locations: the bridge-road transition section(side piers), middle piers, and roadbeds. The results show that the side piers, experience greater accumulation than the middle piers. Similarly, the leeward side of the roadbed witnesses more deposition compared to the windward side. Another finding reveals a reduced sand deposition length as the vertical profile, in alignment with the wind direction, moves further from the bridge abutments at the same clearance height. As wind speeds rise, there’s a decline in sand deposition and a marked increase in erosion around the side piers, middle piers and roadbeds. In conclusion, a bridge clearance that’s too low can cause intense sand damage near the side piers, while an extremely high roadbed may lead to extensive surface sand deposition. Hence, railway bridges in areas prone to sandy winds should strike a balance in clearance height. This research provides valuable guidelines for determining the most suitable bridge and roadbed heights in regions affected by wind and sand.
文摘As the lifeline of social development,road and bridge projects are the main channel to realize resource transportation and economic circulation.Ensuring the quality of road and bridge project construction is crucial for the development of society,the economy,and people’s livelihoods.This paper studies the design of roadbed pavement structures in road and bridge transition sections.It aims to provide technical references and significance for China’s road and bridge engineering design and construction units,promoting scientific and standardized design in these actions.This will contribute to the safety and stable operation of road and bridge projects,offering effective technical support.Furthermore,it seeks to foster the sustainable and healthy development of China’s road and bridge engineering on a macro level.
文摘In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and then processing piles. On the basis of engineering practice, the authors analyzed the influence of foundation treatment on bridge piles in bridgehead transition section by finite-element method (FEM). This research has positive significance in predicting displacement of bridge pile, directing construction of foundation treatment, and improving quality of engineering and so forth.
文摘In this paper,combined with the relevant speed theory and characteristics of the law,the current highway speed transition design problems are studied and analyzed.In the process of specific analysis,mainly combined with the characteristics of different types of highway speed changes and road section design requirements,this paper studies and analyzes the design methods of different types of highway speed transition section.And on this basis,according to the design principles and requirements of highway operation speed transition section,the paper summarizes the matters needing attention in the design of highway operation speed transition section,in order to provide certain reference value for relevant personnel.
文摘Firstly, sample square-circular transition tube along straight central route was modeled on CATIA software. The parameters are as follows： let the tube length is L, and the constant cross section area is S, and S = πR^2 = a2, in which R stands for the circle radius on one end, and a the square side length on the other end; set up the coordinate system with OX axis on the central route in which the origin O is on centroid of the square end and assume the cross section size at x as the square shaped with all four comers filleted in radius r which is proportional to x, that is, the linear slope of r is R/L, thus, both values r and square side length ax can be attained on the constant cross section area assumption. Secondly, some sample polygonal-circular transition tubes along straight, circular and helical central route were implemented similarly. Thirdly, numerical analysis of stress and displacement of these tubes were carried out on MSC/PATRAN software which are important to the distribution of turbulent flow and the layout of these transitional tube structures.
