Volume 45, Issue 3 (2025)
Subgrade Engineering
Discontinuous Deforma tion Analysis of Progressive Toppling of Rock Slopes with Fractured Slab Structure
YUAN Sifan, LI Tonglu, Haider Mumtaz, ZHANG Changliang, and LI Ping
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.001
Progressive toppling of rock sl opes with fractured slab structures is quite common in the slopes of hydropower and highway engineering,posing a potential safety risk during both construction and operational phases.The field investigation found that progressive toppling mostly occurs on slopes with concentrated tectonic stress,intense river incision,and high steepness.Typically,these slopes are composed of hard,thinly-layered,and overthrusted rock mass with a fractured slab structure.From a macroscopic point of view,progressive toppling failure is neither a collapse nor a slide but a form of discontinuous deformation.The traditional limit equilibrium method for slope stability analysis is not suitable for evaluating such slopes.In this paper,by taking the progressive toppling of the slopes along the G 108 Highway in the Qinling Mountains as an example and considering the uplift of the mountain and river downcutting,a discontinuous deformation analysis (DDA ) method was employed to simulate the entire process of progressive toppling,and the mechanisms of its evolution were analyzed.The results show that as the river downcutting progresses,the rock mass experiences interlayer shearing along bedding planes under the influence of gravity,gradually tilting toward the river valley.Once a through-going rupture area develops,it transforms into a landslide failure.For the evaluation of such slopes,a numerical model should be used to simulate the entire deformation failure process.This allows for the estimation of the current state and development trends,providing a basis for reinforcement and management.
Prediction for Humidity Adjustment Factor and Dry-Wet Cycle Reduction Factor of Resilient Modulus of Subgrade Soil Based on ANN
WANG Xufeng, FU Wei, PENG Junhui, HU Jiankun, ZHANG Junhui, and LI Zhiguang
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.002
Existing methods for determining the humidity adjustment factor and dry-wet cycle reduction factor of the resilient modulus of subgrade soil are mostly based on laboratory tests that consume a large amount of manpower and time,and the prediction accuracy is limited due to the constraints of specification value ranges.In order to achieve fast and accurate prediction of these two factors,the effects of stress state,moisture content,and the number of dry-wet cycles on the resilient modulus of subgrade soil were investigated through laboratory dynamic triaxial tests.Based on existing literature,physical parameters,state parameters,and stress parameters of subgrade soil were selected,and an artificial neural network prediction model optimized by a genetic algorithm was developed to enable rapid prediction of the humidity adjustment factor and dry-wet cycle reduction factor of subgrade soil.The results show that moisture content and dry-wet cycles have a significant influence on the resilient modulus of subgrade soil,while the humidity adjustment factor and dry-wet cycle reduction factor show stress dependence.The intelligent prediction model demonstrates high prediction accuracy for both the humidity adjustment factor and the dry-wet cycle reduction factor.
Experimental Study on Engineering Performance of Post-Planted Precast Concrete Pile with Prebored Grouting
ZHAO Yu, WANG Wei, JIANG Lei, SONG Zhenya, and ZHANG Hao
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.003
The traditional piling methods of precast concrete (PC) piles are difficult to pass through the hard soil layers and tend to induce severe soil squeezing effects.To address this issue,the technology of a post-planted PC pile with prebored grouting was analyzed.Based on the project of the Hefei‒ Zongyang section of G3W Dezhou ‒ Shangrao Expressway,the bearing characteristics of post-planted PC piles were researched by the load tests of five piles in two different field test sections.The results show that the bearing capacity of the PC piles can be effectively improved by setting the cement mortar coating layer around the PC piles.The settlement of the pile top under the engineering design load is only about 1.96‒3.28 mm.By considering the structural characteristics of the composite pile body,the resistance of the interface between the inner PC pile and the outer cement mortar changes from large at both ends to small in the middle,and the resistance of the interface between the cement mortar and the surrounding soil increases with the depth,which indicates that the cement mortar coating layer can effectively transfer the load of the inner PC pile,enlarge the diameter of the post-planted PC pile,and reinforce the pile body.
Pavement Structure and Materials
Research on Evaluation Index of Low-Temperature Semi-Circular Bending Test of Asphalt Mixtures
LYU Songtao, CHEN Qi, LU Weiwei, ZHAO Pei, and WANG Jinping
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.004
This article aims to investigate the low-temperature crack resistance performance of asphalt mixtures under different aging conditions and loading rates and select appropriate indicators to accurately characterize and quantify their performance.Based on the semi-circular bending test,the influence of different aging degrees (unaged,short-term aged,long-term aged for three days,and long-term aged for five days ) and loading rates (50 mm/min,5 mm/min,0.5 mm/min,and 0.1 mm/min ) on the low-temperature performance of asphalt mixtures was investigated.The evaluation effect and applicable range of five crack resistance performance indicators,namely fracture energy (Gf),stress intensity factor (KIC),flexibility index (IFI),crack resistance index (ICRI),and balanced cracking index (IBCI),were studied through variance analysis and variability analysis.The results indicate that aging significantly decreases the low-temperature performance of asphalt mixtures.After short-term aging,Gf decreases by approximately 26%,and as the degree of aging deepens,it continues to decrease at an attenuation rate of about 3%.As the loading rate increases,the evaluation effectiveness of IFI and IBCI deteriorates.Conducting the semi-circular bending test at a loading rate of 0.1 mm/min provides a more comprehensive evaluation of the low-temperature performance of asphalt mixtures.The results of variance analysis and variability analysis indicate that Gf and ICRI can significantly characterize the influence of aging and loading rate on the low-temperature performance of asphalt mixtures.The variability of IFI and IBCI is significantly higher than that of the other three indicators.Hence,it is recommended to adopt Gf and ICRI from the semi-circular bending test as more reasonable indicators for evaluating the low-temperature performance of asphalt mixtures.
Research on Pavement Crack Segmentation Based on Swin-U
WANG Hua, WANG Liangcai, XIONG Feng, and HU Jing
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.005
To address the issues of overfitting,low computational speed,and insufficient target information extraction in pavement crack segmentation tasks,this study proposed a Swin-U network model based on the U-Net architecture.The model adopted the Swin-Transformer as the feature extraction module to enhance the model ’s fitting capability and enable more accurate crack feature extraction,thereby enhancing segmentation accuracy.Additionally,a stable loss function,Focal Loss,was introduced to improve the accuracy of target segmentation.Experiment results on a proprietary pavement crack dataset show that the Swin-U network model achieves pixel-level segmentation of crack images and significantly outperforms the traditional U-Net.On the test set,it improves the intersection over union and F 1 score by 25.00% and 27.61%,respectively.This improved model not only provides more reliable technical support for road maintenance decision-making but also offers a reference for the optimization of pavement crack segmentation methods.
Study on Salt Release Mechanism of Self-Melting Ice Asphalt Mixture and Its Impact on Road Performance
LI Tao and ZHANG Xiu ’ang
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.006
To study the long-term salt release characteri stics of self-melting ice asphalt mixture and the impact of the complete salt release on pavement durability,an accelerated salt release method was developed using a Los Angeles abrasion tester.The salt release mechanism under varying asphalt types,deicing agent contents,and gradation types was revealed.The impact of the complete salt release on road performance was analyzed.Results show that the Los Angeles abrasion tester-based salt release method achieves 91 times and 114 times higher salt release efficiency than the magnetic stirrer and natural immersion methods,respectively.SBS-modified asphalt mixture exhibits a longer salt release duration.The salt release duration is proportional to the deicing agent content.The SMA- 13 self-melting ice asphalt mixture shows relatively poor salt release uniformity.After complete salt release,the high-temperature stability of the self-melting ice asphalt mixture decreases by 31.6%,low-temperature performance by 15.4%,and water stability by 26.7%.
Long-Term Water P ermeability Performance of Asphalt Mixtures under Wide-Scope Void Ratio
CHEN Sanxi, GUAN Hongxin, YAO Ming, MO Zhiwei, and JIANG Wangheng
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.007
In order to compare the water pe rmeability performance of asphalt mixtures with different void ratios after scouring and clogging,self-developed equipment was adopted to conduct vertical water permeability tests,dynamic water scouring-based water permeability tests,water pressure tests,and simulated clogging tests on semi-open-graded DK- 13 mixtures with void ratios of 9%,11%,and 13%,as well as open-graded PA- 13 mixtures with void ratios of 15%,17%,and 19%.The experimental results show that:① The water permeability performance of the asphalt mixture becomes better as the void ratio increases.The water permeability coefficient changes relatively small after the void ratio of the asphalt mixture reaches 15%,which is attributed to the fact that the water pressure curves on the top and bottom of the specimens basically overlap;② The initial water permeability performance of semi-open-graded asphalt mixtures is much weaker than that of open-graded asphalt mixtures,and the water permeability performance still follows this regularity after dynamic water scouring and clogging test;③ Semi-open-graded asphalt mixture is more prone to clogging,and the degree is more severe.The water permeability coefficient of asphalt mixture with a void ratio of 13% changes the most after scouring.It can be seen that scouring makes asphalt mixtures more easily suffer from water permeability,while clogging makes the opposite regularity.The asphalt mixture with a void ratio of 13% is most affected by scouring.
Research on Size Effect on Cubic Compressive Strength of Ground Granulated Blast Furnace Slag-Fly Ash Stabilized Large-Size Macadam
LIU Qunyan, LIU Liping, HE Miao, YUAN Lingqing, and ZHANG Liang
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.008
To analyze the effect of specimen size on the compressive strength of ground granulated blast furnace slag-fly ash (GGBFS-FA ) stabilized large-size macadam,the 200 mm × 200 mm × 200 mm cubic specimen and 3 d compressive strength were designated as a reference specimen and strength in this study,and numerical simulations of compressive strength were performed by using a discrete element method for GGBFS-FA stabilized large-size macadam specimens with a maximum particle size (dmax) of 73 mm and five side lengths of 2.0dmax,2.5dmax,3.0dmax,3.5dmax,and 4.0dmax.The size effect mechanism on the mixture ’s compressive strength was revealed from the perspective of energy.By comparing the applicability of the improved Ba žant size effect theory model and the exponential size effect empirical model to the size effect on the mixture compressive strength,the critical size of the specimen and the strength conversion factor were proposed.The results suggest that the compressive strength of GGBFS-FA stabilized large-size macadam shows a significant size effect,and it decreases with the increase of specimen size.When the specimen size exceeds 3.0dmax,a decrease in the total energy and elastic strain energy gradually stabilizes,resulting in a weakening of the size effect on the compressive strength.Compared with the improved Ba žant size effect theory model,the exponential size effect model is more suitable for the size effect on the mixture compressive strength.It is recommended that the critical size of the compressive strength specimen for GGBFS-FA stabilized large-size macadam be set at 256 mm,and the compressive strength of the specimen is 95% that of the reference specimen.
Semi-Flexible Pavement Structure Analysis Based on Double Modulus Theory
PAN Qinxue, ZHOU Shurui, HU Jia, ZHANG Long, SONG Xiaojin, and LIU Hongfu
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.009
Semi-flexible pavement materials have significant differences in tension and compression.If the mechanical response analysis of pavement structures is conducted by using the traditional linear elastic theory with a single modulus,there will be a considerable deviation from actual situations.To analyze and optimize semi-flexible pavement structures,this paper compared the changes in key mechanical responses of pavement structures under six different semi-flexible layer positions and thickness combinations based on the double modulus theory.The results show that there is a significant difference in the calculation results of key mechanical responses of the pavement based on the double modulus theory and the single modulus theory,with the difference in the maximum longitudinal tensile strain of the pavement being the most significant (over 60%).Compared to other layer combinations,when the upper or middle layer is composed of a semi-flexible pavement material,the surface deflection is larger,and the overall stiffness of the pavement structure is smaller.When the middle-lower,lower,or upper-middle-lower layers contain semi-flexible pavement materials,the tensile stress at the bottom of the lower layer is high,which makes it prone to cracking.When the middle-upper layers contain semi-flexible pavement materials,the critical mechanical response is relatively small,and it is recommended that the upper-middle layer be the optimal application layer.A model for the relationship between the key mechanical responses and the thickness of the semi-flexible layer was established.The maximum tensile stress on the road surface is most significantly affected by the thickness of the semi-flexible layer (up to 64%).When the semi-flexible material is applied to the upper-middle layers,the optimal thickness range is 10–12 cm.The research results can provide reference for the design of semi-flexible pavement structures considering the differences in tension and compression.
Effect of Mineral Admixtures on Properties of Shotcrete
MA Kaikai, ZHAO Feng, SUN Rongxiao, HAN Song, HU Peng, and WANG Kun
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.010
To study the influence of different mineral admixtures on the properties of shotcrete,the effects of four kinds of mineral admixtures including fly ash,silica fume,metakaolin,and carbon black on the rebound rate,one-shot thickness,and compressive strength of shotcrete were analyzed through tests on concrete rebound rate,one-shot thickness,and compressive strength.The results show that:① as the content of carbon black,silica fume,and metakaolin increases from 5% to 10%,the rebound rate of shotcrete decreases by 25.76%,16.46%,and 16.70%,respectively;② carbon black and silica fume have a good effect on increasing the one-shot thickness of concrete.When the content of carbon black and silica fume is 10%,the one-shot thickness exceeds 35 cm;③ carbon black can easily cause strength loss in shotcrete.The compressive strength of concrete added with 10% carbon black decreases by 10.7 MPa and 15.2 MPa after 7 days and 28 days,respectively.This study provides theoretical support for the application of fly ash,silica fume,carbon black,and metakaolin in shotcrete.
Study on Rheological Properties of Basalt Fiber Asphalt Mastic Modified with Silane Coupling Agent
LIU Yuande, ZHENG Nanxiang, ZHANG Xiang, GAO Haiwei, and ZHANG Bowen
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.011
To investigate the rheological properties of basalt fiber asphalt mastic,a silane coupling agent was used as a modifier for basalt fibers,and the effects of varying fiber contents were analyzed. Cone penetration tests,bending beam rheological tests,and dynamic shear rheometer tests were conducted to evaluate the rheological properties of asphalt mastic consistency, high-temperature stability,and low-temperature cracking resistance under different temperatures and fiber contents.The findings show that the silane-coupled basalt fibers enhance the shear strength and consistency of asphalt mastic.After modification,the phase angle decreases;elastic response increases,and complex modulus improves.Adsorption capacity between fibers and asphalt increases significantly,enhancing high-temperature deformation resistance and low-temperature cracking resistance of asphalt.The optimal fiber content for silane-coupled basalt fibers is approximately 2.6%.
Bridge Engineering & Tunnel Engineering
Structural System Reliability Analysis Method for Cable-Supported Bridges Based on Deep Belief Networks
CHEN Zhenyu, XIE Bo, and LU Naiwei
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.012
Aiming at the high-precision reconstruction of structural function functions caused by the strong nonlinearity of cable load-bearing bridge structures,this study presented a structural system reliability analysis method based on a deep belief network (DBN ).A long-span suspension bridge was used as the engineering background to identify the dominant fault path of the structural system and analyze the law of structural fault path transfer caused by the deterioration of the suspender strength.Numerical analysis results show that DBN can capture the nonlinear mechanical behavior of the finite element model of the suspension bridge,thereby making the implicit statically indeterminate functional function explicit and realizing the rapid calculation of component reliability indices.According to the search results of the fault path of a certain suspension bridge,the fault order is suspender,stiffening beam,and main cable.The reliability index of the structural system calculated from the three-layer fault tree is 9.63.The coupling effect of corrosion fatigue damage of the suspender causes the reliability index of the suspension bridge structural system to decrease rapidly.The replacement cycle in the case of the target reliability index is 26 years.The analysis results can provide a theoretical basis for the formulation of suspender replacement cycles and strategies.
Research on RC-UHPC Composite Slab Frame Culvert Technology in Wave-Affected Areas
QIU Junfeng
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.013
To address the problems in the construction of offshore bridges and culverts such as the structures susceptible to waves,limited layout,and high cost of soft foundation treatment,this paper proposed a new technical solution for reinforced concrete and ultra-high performance concrete (RC-UHPC ) composite slab frame culverts.With supporting engineering,the ordinary box culvert was selected as a comparison scheme for technical and economic analysis,and the design points and construction procedures of new structures were introduced.Based on the calculation results of the overall bearing force,the bearing performance of the top slab under different load conditions was analyzed,along with an investigation of the secondary internal force resulting from the shrinkage and creep effects of the beam slab and the overall temperature deformation of the structures.The results show that compared with those of the ordinary box culvert,the concrete usage of the RC- UHPC composite slab frame culvert is reduced by more than 40%,and the total cost drops by more than 10%.The high toughness and durability of UHPC enable the structures to avoid premature cracking and other damage,thereby lowering full life cycle costs.Its bearing performance caters to the design requirements under operating and extreme wave conditions.As secondary effects resulting from shrinkage,creep,and temperature are significant,corresponding design and construction control measures can be taken to reduce the adverse influences of secondary effects.The RC-UHPC composite slab frame culvert provides a new and more applicable option for the construction of bridges and culverts in wave-affected areas,which can provide a reference for subsequent similar engineering applications.
Inverse Analysis of Thermal Parameters of Concrete Box Girder Based on DE-BP Neural Network
YAO Yong, YAN Yu, SUN Bo wen, WANG Yuesong, and JIANG Tianyong
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.014
In view of temperature cracks in concrete box girders easily occurring during construction,an inverse analysis method based on uniform design theory and differential evolution back propagation (DE-BP ) neural network was proposed to accurately obtain the thermal parameters of concrete box girders and ensure the reliability of temperature analysis of concrete box girders.This method established the nonlinear relationship between the temperature peak of characteristic points and the thermal parameters through the DE-BP neural network.By using the uniform design method and the Abaqus finite element numerical model,130 sets of sample data were generated.Based on the ratio of 12∶1 for training samples to test samples,the back analysis model was trained.The results show that the mean absolute percentage errors EMAPE of the DE-BP neural network model are all less than 3%,and the relative errors are less than 5%.This indicates that the prediction accuracy of the BP neural network can be effectively improved by the DE algorithm.The maximum error of the temperature peak for the characteristic points based on inversion analysis is 2.05 ℃,and the calculated temperature histories are in good agreement with the actual ones.In a word,the back analysis method of thermal parameters for the concrete box girder based on the DE-BP neural network and uniform design theory demonstrates high accuracy and a stable inversion process with good reliability,which can provide a theoretical basis for temperature control of other similar projects.
Research on Key Construction Monitoring Technology of Long-Span Skewed Arch and Curved Beam Bridge
XU Yufeng, ZHANG Zhantao, XIE Yunfei, and LI Zihui
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.015
As a new structure with sloping arch ribs and curved main beams,a skewed arch and curved beam bridge markedly differs from the conventional bridge in construction monitoring technology due to its complex structure and prominent spatial effect.To investigate the key technology in construction monitoring,this study took a long-span skewed arch and curved beam bridge as the engineering background and discussed construction process simulation analysis,field monitoring,and parameter identification and adjustment of the bridge.The results show that the plate-shell unit model has higher calculation accuracy and can comprehensively show the stresses in all directions of the bridge compared with the beam element model.Additionally,in response to the limitations of the traditional influence matrix method in cable force adjustment,an improved method based on sequential quadratic programming optimization was proposed,addressing the issue of inapplicability in cable force optimization.The research findings can provide theoretical references and technical support for the construction monitoring of similar bridges.
Study on Aerodynamic Optimization of Π-Shaped Cable-Stayed Bridge with Vortex-Induced Vibration in Mountainous Areas
ZENG Min, LIU Hanyun, MAO Na, CHEN Baixiang, HAN Yan, and LI Chunguang
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.016
Given vortex-induced vibrations of bridges caused by high wind attack angles in mountainous canyons,this study investigated the vortex-induced dynamic characteristics of a Π-shaped steel-concrete composite beam cable-stayed bridge in a mountainous canyon under high wind attack angles based on wind tunnel tests and examined aerodynamic measures for vortex suppression.Firstly,a finite element model of the bridge was established,and the dynamic characteristics of the bridge in both the completed and construction states were analyzed.Subsequently,a 1∶50 scale detailed segment model was designed based on similarity theory to analyze the vortex-induced vibration performance of the original main beam under conventional wind attack angles of ± 3° and 0°,as well as the high wind attack angle of ± 5°.Then,the influence of a single aerodynamic measure such as L-shaped deflector plates,wind fairings,and lower stabilizing plates,as well as their combinations,on the vortex-induced vibration performance of the Π-shaped main beam was studied.Finally,the optimal aerodynamic measures and their performance improvements were proposed.The research reveals that the vortex-induced vibration performance of the Π-shaped beam cable-stayed bridge is poor,and significant vortex-induced vibrations occur at all five typical wind attack angles under low wind speeds.The single aerodynamic measure fails to control vortex-induced vibrations of the Π-shaped main beam.The combination of the 1# wind fairing + lower stabilizing plate exhibits excellent vortex suppression effects,reducing the corresponding vortex-induced response displacement by over 95%.The research results can provide valuable insights for similar real-world engineering projects.
Wind Tunnel Experiment on Wind-In duced Vibration Performance of Arch-Shaped Inclined Steel Bridge Tower in Construction Free-Standing State Using Ae roelastic Model
XU Peijun, DENG Fei yun, CHEN Shixuan, and ZHANG Jiren
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.017
This paper presented a wind tunnel experimental study on the wind-induced response characteristics of a rectangular-sectioned arch-shaped inclined steel bridge tower during the construction free-standing stage.A 1:50 scaled aeroelastic model was employed to conduct experiments at different wind yaw angles β (0°‒180°).The experimental results indicate:① under the uniform flow field,the tower in its free-standing state does not experience galloping when the bridge ’s wind speed reaches 60 m/s;② under the uniform flow field,the tower exhibits bending vortex-induced vibrations (VIVs ) along the bridge direction or transverse to the bridge direction.However,the amplitudes of the tower top displacements associated with these VIVs are relatively small,thereby posing minimal adverse effects on the comfort of construction personnel and the safety of construction machinery;③ under the turbulent flow field,the tower only exhibits a low-speed bending VIV transverse to the bridge direction at a wind yaw angle of 75°.Compared to those of the uniform flow field,the amplitudes of the tower top displacements associated with the VIV are lower,indicating a suppressing effect of turbulence on VIVs.These research findings provide an essential reference for the design and construction of arch-shaped inclined steel bridge towers.
Analysis of Mechanical Properti es of Integral Jacking Basket Arch Bridge during C onstruction
CHEN Tao, QIU Jingkui, and WANG Ji
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.018
Taking the Xindian Bridge in Ni ngbo as the background,this paper analyzed the mechanical properties of the integral jacking basket arch bridge during construction.Midas finite element software was used to establish the spatial model of the main bridge,and the deviation of the suspender force and support reaction force of the completed bridge from the design was 1.84% and 1.8%,respectively.The maximum deviation of the displacement calculation of the tie beam at the bridge completion stage was 22 mm,and the maximum deviation of the displacement of the arch rib at the same stage was ‒ 12 mm,which showed that the finite element model simulation method was correct and reliable.During the jacking process,the maximum shear stress of the tie beam calculated based on the truss unit was 112 MPa,which was less than the design strength value of 160 MPa in the specification.According to the calculation method of bearing stiffeners at the support in the specification,the checking result of the local bearing strength of the tie beam was 114 MPa,less than the 355 MPa required in the Specifications for Design of Highway Steel Bridge (JTG D 64‒2015 ).The local instability result was 234 MPa,less than 275 MPa required in the specification.According to the analysis of the local model,the equivalent stress of the web calculated by the fourth strength theory was 181.7 MPa,and that calculated by the third strength theory was 204.4 MPa.The results met the requirements of the allowable stress of 252 MPa in the specification.Due to the large force on the web and the insufficient surplus,the shear stress was reduced from 112 MPa to 95 MPa when the forced displacement value of the fulcrum was 2 cm,and no failure and yield of the plate appeared in the whole process of the bridge jacking,which showed that the calculation method and results could guide the actual construction.Two working conditions were calculated for system conversion:① Symmetrical removal from the center to the edge;② symmetrical removal from the edge to the center.The analysis results show that the two schemes have little influence on the structural force,but the scheme featuring symmetrical removal from the center to the edge has relatively little deformation of the beam arch,which is beneficial to the installation of the suspender.
Numerical Simulation Study on Scour Erosion of Bridge Pile Foundations in Service
WANG Shang, MI Jiangchuan, CHEN Mingtao, SONG Dan, ZHANG Qiao, ZHANG Yong, and WANG Weixiao
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.019
Bridge pile foundations in servic e are subjected to long-term scour erosion caused by sediment-laden water flow,leading to a gradual expansion of the eroded and worn areas.This in turn results in varying degrees of damage to the pile foundation structure and reduces the durability and safety of the bridge.In order to study the impact of scour erosion on bridge pile foundations,this study took the Hanjiang No.1 Bridge in Ankang City as the research object.The ANSYS FLUENT software was used to conduct three-dimensional numerical simulations of the pile foundation and analyze the distribution characteristics and patterns of scour erosion under different conditions.The results show that:① Scour erosion areas are mainly concentrated on the upstream surface of the pile cap,the joint between the pile and the cap,and both sides of the pile shaft;the downstream surface of the cap and the downstream side of the pile shaft experience less erosion.The erosion effect of sediment on the pile foundation is mainly due to impact and cutting;② Under the same sediment concentration,smaller sediment particle size results in a larger scour erosion area.Increases in flow velocity,sediment particle size,sediment concentration,and pile diameter all contribute to a higher erosion rate,among which flow velocity has the greatest influence.The research results can provide a reference for the design and construction of bridge pile foundations in service.
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.020
This paper is based on a super long-span extradosed cable-stayed bridge with a main span of 400 m.In view of the technical challenges of high negative bending moment at the quarter point of the bridge and large deformation during the cantilever assembly process in the non-cable area,a systematic solution was proposed in combination with the entire construction process.This paper proposed three schemes:permanent cable over-tensioning,temporary cable setting,and large segment closure.The bending moment ratio (λM) and structural deformation were used as quantitative indicators,and a finite element model was established to compare the three schemes.The results show that all three schemes can improve the structural stress and reduce deformation during construction,but each has its own advantages and disadvantages in terms of implementation difficulty,economy,and effect.Based on construction conditions,economic factors,and finite element analysis,a suitable scheme was selected.A combination of over-tensioning and temporary cable setting was adopted for the background project.At the completed stage,the bending moment ratio λM is 1.53 (reduced by 2.47 compared to the original scheme );the tangent assembly deformation is 2.276 m (reduced by 1.175 m).In addition,the temporary cable anchorage structure can be used as the cable replacement and tensioning structure during the operation period,achieving good application results and economic benefits.
Research on Influence of Shield Synchronous Grouting Parameters on Surface Deformation
LUO Xu, ZHANG Zhaofeng, FU Helin, CAO Guiqian, and ZHAO Chuanming
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.021
In order to determine reasonable grouting parameters,control surface settlement,and reduce the risk of excessive surface settlement caused by irrational synchronous grouting parameters,this study studied the shield tunnel project between maglev T 2 station and maglev T 3 station.A numerical simulation method was adopted to study the influence of grouting pressure,grouting volume,and the elastic modulus of slurry on surface deformation.The results show that the tunnel synchronous grouting has a significant effect on surface settlement control.A greater grouting pressure,equivalent grouting layer thickness,and elastic modulus of slurry mean a smaller surface settlement.As the three parameters increase,the variation range of surface settlement decreases and gradually stabilizes,indicating that the grouting effect tends to saturate.By considering both grouting effectiveness and economic efficiency,it is recommended to adopt a grouting pressure of 200‒250 kPa,a grouting volume of 5.4 m3 per ring,and an elastic modulus of slurry between 200 and 250 MPa.The on-site application has verified the rationality of this parameter combination.The research provides a reference for grouting reinforcement in similar shield tunnel projects.
Field Test Research on Optimization of Smooth Blasting Parameters Based on Drilling Speed
WANG Haitao, LU Jianghua, LIU Yang, HUANG Mingli, and WU Xuan
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.022
This study aims to address poor adaptability and timeliness in the design of smooth blasting hole parameters in t he past.With the drilling and blasting method-based construction of large cross-section tunnels in Botanggou and Tielugou along the Zunhua‒Qinhuangdao Expressway as the research background and Ⅲ and Ⅳ grade surrounding rocks of porphyritic granite as the research object,statistical regression analysis and theoretical derivation were conducted on the measured data during on-site drilling according to the rock solidity coefficient.Based on this,a simple parameter design method for a smooth blasting layer based on the drilling speed index of an air leg anchor rod drill was proposed,and the relationship between the drilling speed and the parameters of the smooth blasting layer hole was obtained.The research results indicate that there is a good correlation between the drilling speed and parameters such as the spacing between surrounding holes and the thickness of the smooth blasting layer.Based on the engineering conditions of the Botanggou and Tielugou tunnels,a parameter design table was calculated for the drilling speed of the drill rod,the spacing between surrounding holes,and the thickness of the smooth blasting layer.Through on-site practice,this method achieves good smooth blasting results,with a hole trace rate of over 90%.The research findings can provide a theoretical basis and reference for the design of smooth blasting parameters of tunnels in similar geological conditions.
Study on Reasonable Parameters of Natural Smoke Exhaust Shafts in Tunnels with Different Longitudinal Slopes
YANG Tao, ZENG Yuekai, LI Peijun, REN Rui, DENG Min, and ZHANG Aoyu
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.023
To obtain the reasonable parameters of a smoke exhaust shaft in a tunnel under different longitudinal slope conditions,the temperature,flow velocity,and smoke exhaust efficiency of the tunnel were taken as indexes,and the numerical model was established by using fire dynamics simulator (FDS ) software to study the influence of the longitudinal slope of the tunnel,shaft width,and shaft length on the ventilation and smoke exhaust in case of a fire.The results show that under the longitudinal slope conditions,with the increase in the shaft width and length,the maximum temperature in the tunnel decreases,and the smoke exhaust efficiency of the shaft increases.However,the influence of the shaft width on the maximum temperature and smoke exhaust efficiency is greater than that of the shaft length.There is a correlation between the longitudinal slope of the tunnel and the shaft width.When the shaft width is not greater than 4 m,the increase in the longitudinal slope can effectively reduce the temperature of the vault above the fire source.When the shaft width reaches 5 m,the increase in the longitudinal slope improves the smoke exhaust efficiency.In the positive slope direction,the increase in the longitudinal slope makes the flue gas move faster.Based on the research results and industry norms,this study suggests that the size of the shaft be appropriately increased under the premise of structural safety and the influence of the longitudinal slope of the tunnel be considered.
Smart Road and Intelligent Transportation
Intelligent Vehicle Path Tracking Control Integrating Road Adhesion Constraints
ZHANG Zhiguo, WANG Pu, ZHANG Xinglong, and WANG Yan
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.024
In the field of fault-tolerant control for intelligent vehicle path tracking,the existing methods based on model predictive control (MPC ) have limitations.They often assume that the vehicle model parameters are fixed and ignore the impact of dynamic changes in model parameters,which are caused by factors such as vehicle load changes and external environmental interference,on the path tracking accuracy.When the steering system fails,the front wheel steering angle commands calculated by MPC cannot be directly executed and need to be converted into yaw moment control.Although the existing sliding mode yaw moment control methods have strong robustness,the chattering problem affects the stability and execution effect of the control system.To address these issues,this paper proposed a fault-tolerant control scheme for path tracking that integrated MPC with online model parameter updating and adaptive sliding mode control.By updating the MPC model parameters online,the adaptability to the dynamic characteristics of the vehicle was improved.The adaptive sliding mode control was used to reduce the impact of chattering,and the driving torque distribution was optimized in combination with road adhesion constraints to achieve path tracking.The research results show that the tracking accuracy of the proposed algorithm is better than that of the traditional MPC algorithm,and it can achieve more accurate and stable path tracking control,providing new ideas and methods for the development of intelligent vehicle path tracking control technology.
Reconstruction Plan of Small-Spacing Interchange Connection Sections on Expressway : A Case Study of Xinlong‒Gangkou Interchange on Zhongshan‒Jiangmen Expressway
JIE Qiang and FU Xinsha
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.025
The plan design for the small-spacing interchange connection on the expressway directly affects operational efficiency and driving safety.To achieve the conversion of traffic flow between different expressways,this study explored the reconstruction plan of the connection section under the condition that the interchange spacing did not meet the Design Specification for Highway Alignment (JTG D20‒2017 ) and investigated two connection schemes,including auxiliary lane and collector-distributor lane by taking the Xinlong –Gangkou interchange of the Zhongshan‒Jiangmen Expressway reconstruction and expansion project as an example.The results show that the auxiliary lane is recommended in consideration of the long-term service level,speed coordination,operational efficiency,and engineering scale.The study can provide reference and inspiration for the determination of reconstruction plans for small-spacing interchanges on similar expressways.
Research on Parametric Method of Highway BIM Based on Digital Delivery
LI Jinlong and WANG Xinnan
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.026
By analyzing the application points and the current situation of digital delivery in each stage of highway engineering construction,this study found that the lack of parameter management and definition in the modification and refinement process of building information modeling (BIM ) source files at each stage led to difficulties in the splitting and refinement of BIM at each stage and even the need for reconstruction.To this end,a method for strengthening the overall planning of the whole life cycle was proposed.By clarifying the demand for model parameters according to the application points of each stage,a mechanism for parameter reservation and classification was developed.The parameters,including “overall description ”,“local description ”,“section description ”,and “model element ”,were proposed,and the use scenario and classification principle of each parameter were specified in detail,so as to address parameter redundancy and repeated definition caused by parameter reservation.The study shows that the method achieves a clear definition and orderly management of model creation parameters,improves the efficiency of model creation and modification and parameter use,and provides a solution for the parameterization of BIM application in the whole life cycle.
Road Maintenance and Environmental Protection
Distribution Characteristics of Internal Distress and Maintenance Decision-Making for Asphalt Pavement Based on Three-Dimensional Ground-Penetrating Radar
LI Xiaohua, SONG Liang, YE Wei, XIE Xiaodong, YANG Jiangang, and GAO Jie
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.027
The distribution characteristics of internal distress in pavement structures and the corresponding maintenance decisions are crucial for improving road performance and extending service life.Based on three-dimensional ground-penetrating radar (3D GPR ) technology,this study investigated the internal distress of a 12-kilometer section of both driving and overtaking lanes of an expressway in Hubei Province.High-resolution images of internal pavement distress were obtained,and milling maintenance decisions were optimized by employing these images and a modular decision-making model.Through an efficient and non-destructive technique,the distribution characteristics of internal pavement distress were analyzed,and potential distress types were identified,providing a scientific basis for maintenance decision-making.Data analysis revealed the crack rates,damage rates,and distribution characteristics of distresses between different layers and quantified the severity of the damages.Based on the distribution characteristics of distresses,a modular and layered maintenance decision-making method was proposed,and milling treatment plans were developed in response to the crack and damage rates.The study demonstrates that 3D GPR can efficiently and non-destructively identify and assess internal pavement distress and provide accurate data for maintenance decision-making and resource optimization,thus significantly enhancing maintenance efficiency and economic benefits.
Research on Bridge Jacking Decision Based on Carbon Emission Analysis
ZHANG Xinmin, HU Chengze, GAO Hongbo, YANG Yunping, SUN Zhihong, and CAO Hongyou
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.028
To lift the longitudinal section of existing bridges in highway reconstruction and expansion projects due to insufficient under-bridge clearance,this study took the reconstruction of a 32.5 m T-beam bridge in the reconstruction and expansion project of the Guangzhou‒Shenzhen Expressway as the research object.By using a carbon emission factor method,carbon emissions of three reconstruction schemes,including broken-column jacking,conversion of bearing pads into bridge piers,and demolition and reconstruction,were calculated under different lifting heights,and the corresponding construction and installation costs were compared.The results show that when the longitudinal section of the bridge is lifted to a certain height,the economic benefits of the broken-column jacking and the demolition and reconstruction schemes are basically equivalent,but the total carbon emissions of the jacking scheme are significantly lower than those of the demolition and reconstruction scheme.In the broken-column jacking scheme,the carbon emissions from material production,off-site transportation,and direct construction account for 86%,2%,and 12%,respectively.This indicates that material production is the main source of carbon emissions,followed by construction machinery.The jacking renovation scheme not only conforms to the “carbon peak and carbon neutrality ” policy in China but also achieves equivalent economic benefits to the demolition and reconstruction scheme under certain conditions.The research findings can provide a reference for the decision-making of bridge jacking project schemes.
Foreign Highway
Comparative Study on Differences in Asphalt Pavement Design between China and Southern Africa
WANG Qing, LIN Yangyang, YAN Hongxiang, ZHAO Bin, XIA Moxuan, LI Ning, and SI Wei
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.029
To facilitate the successful implementation of projects in the Southern Africa region and promote the application and internationalization of China ’s standards,this study compared the asphalt pavement design systems,construction materials,design parameters,and structural design methods of both regions based on the main asphalt pavement design specifications currently in use in China and Southern Africa.The results show that among Southern African countries,South Africa has a comprehensive and widely applied standard system,while other Southern African countries adopt more varied and less theoretical standards.In contrast,China ’s standard system is complete and highly practical.Due to differences in regional climates,the selection principles and mechanical requirements for construction materials differ between China and Southern Africa.There are also differences in the values and calculation methods of design parameters between the two regions.The pavement structure design methods in Southern Africa are more diverse,while China follows a predetermined process,with the main difference in the application of the comprehensive catalog method.The study summarized the main differences in standards between China and Southern Africa,providing reference to support the internationalization of Chinese standards and guide technical personnel in highway engineering projects in Southern Africa.
Design of Champlain Bridge in Canada
XIE Yaning, ZHOU Yanfeng, and Marwan Nader
Date posted: 6-23-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.03.030
The Champlain Bridge,an iconic gateway spanning the St.Lawrence River in Montreal,showcases not only the excellence of engineering but also becomes an integral part of the city ’s landscape.With a main span of 240 m,the bridge employs a unique single-pylon harp-shaped double-plane cable-stayed structure.The upper pylon is inspired by a tuning fork in its lateral design,while the upper crossbeam artfully mimics the shape of a bow tie,endowing the bridge with a visual beauty that harmoniously blends elegance and strength.The bridge deck,with a total width of 60 m,was the widest double-plane cable-stayed bridge in the world when it was completed.The typical spans of approach bridges on both sides are 80.4 m and 84.0 m,respectively,and the main girder adopts a large cantilever steel-concrete composite box girder.The pier design is equally distinctive,featuring W-shaped steel pier caps that complement the inclined pier shafts,enhancing the visual hierarchy of the structure.The exposed structural elements collectively form a unique landscape element,seamlessly blending into the local temporal and spatial environment.The main bridge foundation utilizes cast-in-drilled-hole piles,while the approach foundations primarily adopt spread footings,with a few exceptions using piles.Based on construction and transportation conditions,the gird height and span were determined,and a rational structural segmentation was implemented.The industrialized construction techniques,featuring extensive use of precast segments,encompass the main girder,steel pier caps,pier shafts,and spread footings.This significantly improves product quality and efficiency while reducing environmental impact during construction,embodying the concept of green construction.
