Volume 45, Issue 1 (2025)
Highway disaster prevention and service safety in extreme plateau environments
Mechanism of Mud Pumping on Plateau Highway under Traffic Loads and Its Treatment Strategy
ZHANG Junhui, CHEN Zhide, GAO Feng, NA Qicai, MA Pengfei, and XIAO Lin
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.001
The dynamic hydraulic response and particle migration of subgrade structures under traffic loads are fundamental to reveal the formation and development mechanisms of mud pumping.The driving mechanism of fine particle migration in the mud pumping state was explored by conducting laboratory tests on layered gravel-sandy silt columns under dynamic loads.The results show that the slurry sloshing causes alternating positive and negative pressure gradients within the gravel layer.This oscillating pressure gradient enhances the pore permeability in the underlying sandy silt layer,providing the necessary hydrodynamic conditions for fine particle migration.Fine particle migration increases the slurry turbidity to a stable value.Upon the removal of dynamic slurry loading,the fine particles quickly settle and fill the gravel pores,forming a muddy interlayer,which significantly reduces the vertical permeability of the gravel-sandy slit column.Based on the engineering practice of treating mud pumping on the G 0615 Dema Expressway (Huashixia to Jiuzhi Section ) in Qinghai Province,it was found that an important driv er for mud pumping formation is the infiltration of rainfall and snowmelt water through the asphalt surface layer,and this water can even form “water pockets ” within the subbase.When vehicles pass,the deformation of the pavement structural layers causes the slurry in the pores of the water-stable base layer to be squeezed upward through cracks,leading to continuous erosion and damage to the gravel materials.By considering construction difficulty,economic costs,and the ecological environmental protection requirements of the Qinghai‒Xizang Plateau,different treatment methods such as grouting repair and sealing,as well as milling and sealing were adopted,respectively based on the severity and level of the hazard.These methods have played a positive role in sealing and reinforcing the water-stable base layer and reducing pavement permeability.The research provides valuable insights for understanding the development patterns of mud pumping,effectively enhancing the treatment capabilities and promoting high-quality maintenance of plateau highways.
Risk Zoning of Hazards along Highways to Xizang Based on Information Model
LIU Weimin, GUO Guanmiao, CAI Qing ’e, YU Xueyong, DONG Xiaobo, and CHEN Peicong
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.002
The frequent occurrence of hazards along the highways in the Qinghai ‒ Xizang Plateau seriously affects road traffic and threatens the security of lives and property of the people.Conducting a risk zoning assessment of hazards along the highways to Xizang is crucial to enhancing hazard prevention and mitigation.This paper summarized the regional geological environment and development patterns of hazards along the highways to Xizang and analyzed the overall performance of highway traffic operations.On this basis,the Xinjiang‒Xizang Highway was taken as the research object,and the evaluation factors were selected based on the regional geological environment and the main controlling factors of meteorological hazards.By using an information model based on multi-source data fusion,a risk assessment model was established for flood hazards,geological hazards,and comprehensive hazards along the Xinjiang‒Xizang Highway.The information value of different evaluation factors was obtained,and the susceptibility maps for flood hazards and geological hazards,a risk zoning map,and a comprehensive hazard risk zoning map were drawn.The results show that high and extremely high-risk zones for geological hazards contain 96.09% of the known geological hazard risk points,and the high and extremely high-risk zones for flood hazards include 94.74% of the known flood hazard risk points.The comprehensive hazard risk zoning map shows that the high and extremely high-risk zones contain 95.76% of the known hazard risk points.These maps demonstrate the actual hazard risks along the highways to Xizang,validating the effectiveness of the proposed method.
Seismic Performance of Bridge Pile Foundation Considering Effects of Material Freeze-Thaw Deterioration and Permafrost Degradation
ZHANG Xiyin, YU Shengsheng, WANG Wanping, and WEN Hairong
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.003
In cold and high-seismic regions,such as the Qinghai‒Xizang Plateau in China,the deterioration of material properties caused by freeze-thaw cycles and permafrost degradation due to climate change have become increasingly severe,posing significant challenges for the seismic performance assessment of bridge pile foundations.To systematically investigate the impact of permafrost degradation and material freeze-thaw deterioration on the seismic performance of bridge pile foundations and ensure proper seismic design,a finite element model was established,considering the dual effects of permafrost degradation and material freeze-thaw deterioration.A comparative analysis was conducted to evaluate the influence mechanisms of various factors on the seismic performance of bridge pile foundations in permafrost regions.The results indicate that as the bridge service life increases,the horizontal bearing capacity,equivalent stiffness,and energy dissipation capacity of the pile-permafrost system all show a decreasing trend.Notably,the combined effect of permafrost degradation and material freeze-thaw deterioration has a more significant impact on the seismic performance of the bridge pile foundation.Specifically,after 100 years of bridge service,the horizontal bearing capacity of the pile-permafrost system reduces to approximately 55% of its initial value,whereas when only permafrost degradation is considered,the horizontal bearing capacity drops to around 89% of its initial value.Therefore,neglecting the effect of material freeze-thaw deterioration will lead to an unsafe seismic performance assessment of the bridge pile foundation.In the seismic performance analysis of bridge pile foundations in permafrost regions,it is essential to consider not only the effect of p ermafrost degradation but also the impact of material freeze-thaw deterioration.
Cracking Characteristics of Cement-Stabilized Macadam with Early Strength Agent under Variable Temperature and Humidity Curing Conditions
GE Dongdong, LIU Dingyuan, LYU Songtao, JIANG Xiangyang, XUE Yanhua, and YU Yang
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.004
In environments with large temperature variations and low humidity,the curing conditions of cement-stabilized macadam fail to meet the specifications,leading to slow early strength development and increased susceptibility to cracking.This study aimed to investigate the effects of actual environmental temperature,humidity,curing age,and addition of early strength agents on the cracking characteristics of cement-stabilized macadam.Variable temperature conditions were determined based on actual environmental temperature data.Four curing conditions were set by combining temperatures (variable temperature and standard temperature ) with relative humidity of 95%,80%,and 65%,respectively.Three types of specimens were prepared with 0%,10%,and 15% early strength agent contents and cured for 14 and 28 days,respectively.The cracking characteristics of the specimens were evaluated through splitting tensile strength tests,four-point bending flexural strength tests,four-point bending flexural modulus tests,and semi-circular bending tests.The results show that under variable temperature conditions,the cracking characteristics of cement-stabilized macadam,including strength,rigidity,and toughness,are lower than those under standard temperature conditions.Among them,the decrease in splitting fracture work is the most significant at 31.74%,while the reduction in flexural modulus is the smallest at 8.60%.Lower curing humidity indicates an increased susceptibility of cement-stabilized macadam to cracking.The incorporation of early strength agents can mitigate the negative effects of curing conditions.Scanning electron microscope (SEM ) observations reveal that variable temperature or lower humidity reduces the degree of cement hydration,while the addition of early strength agents enhances it.Based on correlation and reliability analysis,the four-point bending test is recommended for assessing the cracking characteristics of cement-stabilized macadam.
Identification and Prediction Model for Traffic Blockage State of Highways to Xizang
WU Ling, LIU Jianbei, ZHANG Zhiwei, SHAN Donghui, and CHI Gandu
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.005
To identify the traffic blockage state on highways to Xizang in extreme environments,comprehensive evaluation indicators for traffic blockage state based on the entropy-weighted TOPSIS method were proposed by using the traffic blockage event parameters observed on four major highways to Xizang:Sichuan ‒ Xizang Highway,Yunnan ‒ Xizang Highway,Qinghai ‒ Xizang Highway,and Xinjiang ‒ Xizang Highway.The K-Medoids clustering algorithm was used to categorize the traffic blockage state into different levels.By considering factors such as hazard types,road types,traffic volume,and vehicle type ratios,a classification model for the traffic blockage state on highways to Xizang was constructed based on machine learning algorithms.The results show that the Qinghai ‒ Xizang Highway has the highest average blockage duration,length,and severity.The Sichuan‒Xizang Highway,while having a slightly lower duration compared to the Qinghai‒Xizang Highway,has a shorter average blockage length,resulting in a lower overall severity of blockage events.Compared with the Yunnan ‒ Xizang Highway,the Xinjiang ‒ Xizang Highway has a higher average blockage duration,yet both have shorter traffic blockage length,leading to lower blockage severity.The identification model based on entropy-weighted TOPSIS and K-Medoids clustering can effectively distinguish between different levels of the traffic blockage state on highways to Xizang.The LightGBM algorithm achieves the highest accuracy on the test set,with an accuracy rate of 96.5%.The results indicate that due to differences in geological terrain,climate,traffic volume,and primary functions of each route,there are differences in the traffic blockage characteristics.The model proposed effectively classifies and predicts the traffic blockage state on highways to Xizang with promising accuracy.
Influence of Urease-Induced Calcium Carbonate Precipitation on Frost Heave Characteristics of Saline Soil
LI Jue, WEN Zili, and LIU Zhengnan
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.006
This study investigated the impact of the soybean urease-induced calcium carbonate precipitation (SICP ) technique on frost heave characteristics of saline soil,specifically addressing the frost heave in saline soil used as a subgrade.The relationships between compaction degree,moisture content,volume ratio of the reaction liquid,and curing temperature with the frost heave rate of treated soil were explored.The results show that SICP significantly reduces the frost heave rate of soil samples by over 28%,with the most noticeable improvement occurring under conditions of higher compaction degree and lower moisture content.Additionally,the increased volume ratio of reaction liquid enhances reaction efficiency,while lower curing temperatures are crucial for maintaining urease activity,both of which contribute to the precipitation of calcium carbonate and thereby improve the resistance of saline soil to frost heave.Sensitivity analysis indicates that moisture content and volume ratio of reaction liquid have a significant impact on the frost heave rate of saline soil,while compaction degree and curing temperature exert lesser effects.In conclusion,the SICP technique has been proven to be effective for mitigating frost heave in saline soil,providing insights for subgrade engineering in cold and arid regions.
Prediction and Evaluation of Road Service Performance in Cold Regions Based on Uncertainty Quantification Theory
LIU Yuanyuan, SI Junling, ZHENG Hao, REN Daoju, FAN Shaobing, and QUAN Lei
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.007
In cold regions,road service performance is influenced by various nonlinear dynamic factors under complex hydrothermal environments and freeze-thaw cycles.Traditional empirical and mechanical models exhibit significant limitations in comprehensively considering the impacts of complex environments and conducting quantitative analyses.This study proposed a method to predict and assess the service performance of constructed roads in cold regions.The method integrated deep neural networks with uncertainty quantification theory,addressing the inadequacies of existing models in adapting to complex environments and analyzing multiple influencing factors.By utilizing data from Montana road sections in the LTPP database,the study employed deep neural networks to predict the international roughness index (IIRI).The Morris one-at-a-time method was used to screen key influencing factors,and sensitivity analysis was conducted using the Sobol index to identify the primary factors affecting road service performance.The results indicate that road age,traffic volume,and freezing index are critical factors influencing road service performance,followed by temperature and wind speed,while annual precipitation,solar radiation,and humidity have relatively minor impacts.These findings highlight the significance of screening key factors and conducting sensitivity analyses to discern the primary and secondary factors influencing road service performance in the complex environments of cold regions.The proposed research framework effectively addresses the limitations of traditional evaluation models in adapting to complex environments and analyzing influencing factors comprehensively.It provides theoretical support and practical guidance for accurate prediction and scientific evaluation of road service performance in cold regions.
Permanent Deformation Prediction Model of Subgrade Soil under Freeze-Thaw Cycles Based on LSTM and Transformer
ZHANG Anshun
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.008
To accurately predict the permanent deformation of subgrade soil under the coupling effect of freeze-thaw cycles and traffic loads,a hybrid neural network model based on long short-term memory (LSTM ) and Transformer was proposed,building upon the results of dynamic triaxial tests.This model effectively captured the temporal dependencies and complex interactive effects among input variables,thereby significantly enhancing the accuracy and generalization ability of permanent deformation prediction of subgrade soil.The results indicate that higher confining pressure improves the resistance of subgrade soil to deformation,but its permanent deformation behavior is still significantly influenced by the magnitude of cyclic loading and the number of freeze-thaw cycles.A comparative analysis with traditional empirical regression models validates the superiority of the proposed hybrid model in addressing nonlinear deformation issues.Furthermore,sensitivity analysis results demonstrate that confining pressure and fluid limit are the primary factors affecting the permanent deformation of subgrade soil.This study can provide reference and guidance for the construction of durable subgrade in seasonally frozen areas.In the design stage,it is essential to select fillers carefully and implement anti-freezing structures,while during the operation and maintenance stage,attention should be paid to overloading phenomena.
Pavement Structure and Materials
Analysis of Joint Load Transfer Performanc e of Prefabricated Steel‑Concrete Hollow Pavement Slab
ZHU Guangshan, DONG Zihao, YANG Ye, and WANG Jinshan
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.009
In order to study the joint load transfer capacity of a prefabricated steel-concrete hollow pavement slab,a finite element model was established with ABAQUS to carry out numerical analysis.The variation laws of the maximum deflection value and joint load transfer coefficient of the pavement slab with and without cavitation were compared to analyze the load transfer capacity.The results show that when cavitation occurs in the slab,the load transfer coefficient of the slab decreases with the increase in the cavitation area,but the load transfer coefficient of the slab does not change significantly when the cavitation depth reaches a certain level.When there is no cavitation in the slab,the maximum deflection value of the slab changes obviously with the increase in load,and when the load is greater than 200 kN,the deflection value changes little.Different hollow forms also have a certain influence on the load transfer coefficient of the slab.The joint load transfer coefficient of the prefabricated steel-concrete hollow pavement slab is greater than 97% in any case,and the maximum deflection values of the loaded slab and the non-loaded slab are not higher than 60（0.01 mm）,so the joint can work normally,indicating good joint load transfer capacity and effectively preventing the misalignment problem.
Preparation and Performance of Emulsified Asphalt with High-Temperature Resistant and Wheel Sticking-Free Effects
YAN Han, ZHA Xudong, KANG Xiaogang, GONG Yan, ZHANG Zhengji, and ZHANG Wenshuai
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.010
To address the problem of wheel sticking at high temperatures in the construction process of existing wheel sticking-free emulsified asphalt of tack coat,this paper adopted the composite modification method of 70# and 15# matrix asphalt and waterborne polyurethane resin (WPR ) to prepare hard asphalt-WPR (HA-WPR )-modified emulsified asphalt in accordance with the high-temperature resistant and wheel sticking-free requirements.Through a series of laboratory tests,the technical performance,wheel sticking-free performance,and interlayer bonding performance of the emulsified asphalt were researched and compared with ordinary wheel sticking-free emulsified asphalt and ordinary emulsified asphalt tack coat oil.The results show that the technical performance of the HA-WPR-modified emulsified asphalt meets the specification requirements,and the emulsification effect and storage stability are better.Under the high-temperature conditions at 60 ℃ and 65 ℃,when the blending ratio of HA-WPR-modified emulsified asphalt is 30% of the 70# asphalt,70% of the 15# asphalt (mass ratio of asphalt ),and 5% of WPR (mass ratio of emulsified asphalt ),the adhesion rate is the lowest,only 0.8% and 2.3%,respectively.Compared with the ordinary wheel sticking-free emulsified asphalt and the ordinary emulsified asphalt tack coat oil,its high-temperature resistant and wheel sticking-free effects are significant,and the demulsification speed is fast,which is convenient for optimizing the construction process and improving efficiency.At room temperature and high temperature,the interlayer shear strengths of the HA-WPR-modified emulsified asphalt are higher than that of ordinary wheel sticking-free emulsified asphalt and ordinary emulsified asphalt tack coat oil.Its interlayer bonding strength is higher;the temperature sensitivity is weaker,and it has good technical economy.Therefore,the HA-WPR-modified emulsified asphalt can effectively alleviate the phenomenon of wheel sticking at high temperatures in the construction process of asphalt pavement tack coat,improve the service life of pavement,and reduce the maintenance frequency,and it has a higher cost-performance ratio.
A Review of Performance of Cement- Stabilized Base Materials Containing Recycled Conc rete Aggregate
SONG Chengzhe, LI Jiaquan, KONG Jingxun, ZHOU Changjun, and AN Xing
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.011
Semi-rigid base offers excellent performan ce and is widely used as a high-grade highway subgrade in China.Currently,with a large stockpile of waste concrete in the country,using it as aggregate in pavement base materials is of great significance for environmental protection,energy conservation,and emission reduction.In this paper,the basic performance indicators of recycled concrete aggregate (RCA ) and the performance of cement-stabilized base materials containing RCA,including strength,shrinkage,fatigue,and erosion resistance were reviewed.It finds that the basic performance indicators of RCA are lower than those of natural aggregate.Therefore,the proportion of RCA in base materials may be limited to 20% ‒ 50%.The shrinkage and erosion resistance of RCA-containing cement-stabilized base materials tend to stabilize after 28 days,necessitating appropriate curing during the early stages.Microscopic testing reveals the reasons for the high water absorption rate and high crushing value of RCA,while finite element analysis explains the characteristics of crack development in such base materials.This paper provides practical recommendations for the application of RCA in cement-stabilized base materials.
Research Progress of Modified Asphalt with Graphene Materials
ZHANG Zongwei and HE Kai
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.012
To clarify the research status of mo dified asphalt properties with graphene materials,relevant research literature in China and abroad was consulted to compare the effects of various graphene materials and preparation parameters on asphalt.The results show that graphene,nano graphite sheets,and oxidized graphene can improve the microstructure and road performance of asphalt,increase the service life of asphalt,and reduce the maintenance cost of asphalt.Continuously optimizing the preparation parameters of modified asphalt and exploring the mechanism of modified asphalt with new material not only help the promotion and application of new road asphalt technologies but also reduce energy consumption,pollutants,and carbon emissions,providing new ideas for the future development of road engineering.
Bridge Engineering & Tunnel Engineering
Model Analysis of Axial Compressive Mechanical Properties of Concrete Column Constrained by Textile-Reinforced Engineered Cementitious Composites
MA Gao and WANG Zhaoyang
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.013
In order to avoid the problem of matrix cracking in textile-reinforced concrete (TRC ),a reinforcement method of textile-reinforced engineered cementitious composites (ECC ),namely TRECC composed of textile and high-performance ECC was proposed.However,the research on the axial compressive mechanical properties of TRECC-constrained concrete in China and abroad is still insufficient,and there is a lack of reliable strength and ultimate strain analysis models.A total of 116 axial compression test results of TRC-constrained concrete columns and 125 axial compression test results of TRECC-constrained concrete columns were collected.The confinement mechanisms and failure modes of TRECC and TRC-constrained concrete were compared.Then,the strength models and ultimate strain models of TRECC and TRC-constrained concrete were proposed.By taking into account the contributions of longitudinal and hoop reinforcement to the mechanical properties of the columns,the strength model and ultimate strain model for TRECC-constrained reinforced concrete columns were proposed.For the convenience of practical applications,strength and ultimate strain models were proposed for different types of mesh fabrics.The comparative analysis with the experimental results shows that the models have good prediction accuracy.
Mechanical Performance of Nuts in Tie Rod Assembly of Anchorage System of Suspension Bridge
LIU Zheng, LI Zhao, QIN Guifang, XIE Qinjian, JIANG Yuangen, ZHANG Jiyong, WANG Lei, and MA Yafei
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.014
In order to investigate the stress and fatigue performance of nuts in the tie rod assembly of the anchorage system of a long-span suspension bridge,the finite element software Ansys and Abaqus were used to establish the full bridge model and the local finite element models of the tie rod and the hexagonal nut,respectively.Secondly,the whole process variation law of the synergistic force of the tie rod and the nut under the axial tensile load was revealed.The difference in mechanical performance between slotted nuts and unslotted nuts was compared,and the detailed structural parameters of slotted nuts were optimized.Finally,the static tensile and fatigue load tests of the nut in the tie rod assembly were performed,and the failure mechanism and damage mode of the nut in the tie rod assembly were revealed.The results show that the finite element numerical simulation method proposed in this paper is reliable,and slotting can reduce the stress concentration effect at nut ends.There is an optimal scheme in the three slotting size parameter design schemes.There is no damage to the tie rod assembly under static tensile load.The fracture failure of the tie rod is the main failure feature under fatigue load.The slotted nut has better mechanical performance and can meet the design requirements of 2-million fatigue life.
Installation Direction Design and Construction Control of Sliding Bearing of Continuous Girder Bridge
GUAN Changlu, SUN Xiudong, DONG Hao, and WANG Xingzhou
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.015
Continuous girder bridges can improve the structural stress,increase the structural bearing capacity,and promote ride comfort.However,some continuous girder bridges suffer from issues such as bearing dislocation,upper torsion,and damage to seismic arrestors.To identify deficiencies in current design and construction control,an in-depth analysis of these issues was conducted.The findings reveal the main reason is that the bidirectional sliding bearings (nearly half of the total ) fail to provide horizontal force,and the main sliding direction of the unidirectional sliding bearings is inconsistent with the deformation of the bridge superstructure.In this paper,factors including temperature-induced deformation,material shrinkage,elastic compression,creep,and construction process control of the bridge superstructure were taken into consideration.Control measures for the design and installation direction of continuous girder bridge bearings and new methods for the later installation or adjustment of lateral limit plates were proposed.The paper suggests that the main sliding direction of bearings shall be consistent with the line connecting the sliding and fixed bearings.This approach reduces the number of bidirectional sliding bearings while increasing unidirectional sliding bearings,providing greater horizontal constraints for the bridge superstructure,which allows for structural deformation accommodation and improves stress distribution and seismic performance.
Crack Propagation of Vehicle‑Steel Bridge Deck Slabs Based on Pavement Damage
TANG Sheng, YIN Xinfeng, ZHANG Ming, and YAN Wanli
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.016
In order to study the influence of vehicles under different pavement damage conditions on crack propagation of welded toe at the roof of steel bridge deck slabs,finite element models of suspension bridges,fine vehicles,and local steel bridge deck slabs were established,and multiple groups of obstacle heights were set to simulate pavement damage.The explicit dynamic analysis program was used to simulate vehicle-bridge coupling vibration and extract the forces of vehicles on the steel bridge deck slabs at different lanes,speeds,and obstacle heights.The crack propagation life of the welded toe at the roof was obtained by applying them to a local steel bridge deck slab model.The results show that:①The impact effect of vehicles on the bridge will accelerate the fatigue failure of the steel bridge deck slabs under pavement damage.Driving on normal pavement does not lead to crack propagation of the welded toe at the roof,while the crack propagation life exists under pavement damage;② The crack propagation life of the welded toe at the roof in the same lane decreases with the increase in vehicle speed and decreases first and then increases with the increase in obstacle height;③At the speed of 80 km/h in lane 3,the initial obstacle height at crack propagation of welded toe at the roof exists at 80 mm,and the most unfavorable obstacle height is 100 mm,while at the obstacle height of 60 mm,the initial speed at crack propagation of welded toe at the roof exists at 90 km/h.
Calculation of Socket Depth for Circular Pipe Pier-Bearing Platform Socket Connection
CHEN Jingli, XIAO Feng, WANG Zhigang, WANG Zhihai, and XU Yan
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.017
The minimum socket depth for circular pipe pier-bearing platform socket connection can be calculated according to Article C.0.3 in the Specifications for Design of Highway Precast Concrete Bridges (JTG/T 3365 -05—2022 ).In order to enable engineering designers to fully understand and correctly apply the calculation formula in this article,this paper first introduced the main technical features of the typical connection scheme,as well as the structural failure principles and objectives formulated in the specification of the typical connection scheme.Then,it briefly introduced the experimental research content and results of the typical connection scheme and explained the key construction measures and their functions of the typical connection scheme.Finally,the paper compared the minimum socket depth estimation formula in the specification with experimental research.The results indicate that on the premise of meeting the main technical characteristics and construction requirements of the typical connection scheme,the minimum socket depth calculated according to the relevant formulas in the specifications can meet the structural failure principles and objectives of the typical connection scheme and has a certain safety reserve.
Key Techniques for Constructing Flexible Geosynthetic Reinforced Soil Abutments
YU Xiaoxiao, XU Chao, LI Haoyu, and ZUO Binli
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.018
The flexible geosynthetic reinforced soil (GRS ) abutments offer several advantages,including cost saving,reduced bridgehead misalignment,and good seismic performance,showing great potential for application in transportation engineering both in China and abroad.The flexible GRS abutment is essentially composed of a composite structure formed by closely spaced layers of geosynthetic reinforcement material,and the construction quality and load-bearing capacity are crucial to the success of the project.To ensure construction quality and study the construction process of flexible GRS abutments,a construction site monitoring method was adopted.Based on the experience from the construction of a vehicular overpass on the Wuwei ‒ Yuexi Expressway,the quality control measures for flexible GRS abutment construction were discussed,and key techniques such as reinforced material placement,compaction of fill materials,and stacking of facing panel blocks were described.The results show that the on-site bridge erection status is stable,proving good overall construction quality.Additionally,it is found that appropriate tensioning and fixing of the reinforcement material is beneficial to its performance.The selection of an appropriate compaction method based on site conditions can strike a balance between efficiency and quality,while the external retaining structure ensures the verticality of the wall.
Reliability Analysis of Long‑Span Concrete Box Arch Bridge under Temperature Effect Combinations
ZHENG Junlin, JIANG Youbao, ZHENG Xinhao, and LU Naiwei
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.019
The existing design methods for concrete arch bridge structures do not consider the random characteristics of the eccentricity generated by load effects and overlook the influence of stochastic eccentricity on structural reliability.To address this deficiency,a calculation model for eccentricity under temperature effect combinations was derived.The random characteristics of eccentricity for different sections of the main arch of concrete arch bridges and their sectional bearing capacities were analyzed under different load parameter combinations.By utilizing the Monte Carlo method,reliability indices were computed for different sections of the main arch and different load parameter combinations after considering the random characteristics of eccentricity.The results indicate that considering the random characteristics of eccentricity leads to significant variability in the eccentricity of main arch sections,and the sectional bearing capacity may be governed by tensile strength.Reliability indices vary greatly with changes in the temperature-to-load effect ratio,suggesting that when the temperature-to-load effect ratio is significant,existing designs based on fixed eccentricity may lead to potentially unsafe designs.
Static Performance and Stability of a Multi-Span Hybrid Continuous Rigid Frame Bridge with High Piers
HUANG Yu, LIU Guanyu, YI Jianbo, XING Xuan, SU Miao, and PENG Hui
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.020
In order to study the static performance and stability of a steel-concrete composite continuous rigid frame bridge in Suichang,Zhejiang Province,a single girder and girder lattice finite element model for the whole bridge was established by using Midas Civil,and a local solid finite element model was established by using Ansys.A detailed analysis of the structural displacement and stress state of the bridge in use and the local stress in the solid section of the pier and girder under different loads was carried out.The influence of the pile-bottom restraint stiffness and pier-girder connection form on the overall stability of the bridge was discussed,and the overall stability of the structure under wind and live loads was investigated.The results show that the girder lattice model can better simulate the real stress state of the bridge.Under the action of live load,the overall mechanical performance of the bridge and the overall stability of the bridge structure can meet the requirements of the code.The maximum deflection of the structure is 23.8 mm;the maximum tensile stress of the main girder is 45.5 MPa at the middle of the first span,and the maximum compressive stress is −46.5 MPa at the sixth pier.Under the combined action of loads in the use stage,the maximum deflection of the structure is 106.7 mm;the maximum tensile stress of the main girder is 160 MPa,and the maximum compressive stress is -205 MPa.Increasing the pile-bottom restraint stiffness is conducive to improving the overall stability of the bridge,and pier-girder consolidation is more conducive to bridge stability than bearing connections.
Model Test on Bearing Capacity of Gravity Anchor Foundation Considering Rock Socketed Effect
YIN Jingze, GUO Chao, ZHANG Xinmin, LI Wei, SHI Haiyang, and FU Baiyong
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.021
The calculation of the bearing capacity of traditional gravity anchor foundation instructed by Code for Design of Ground Base and Foundation of Highway Bridges and Culverts (JTG D 63—2007 ) only considers the friction effects of the basement and neglects the rock socketed effect of bottom plate,which is simply regarded as a safety margin,on the improvement of bearing capacity.To study the influence of rock socketed effect on the bearing capacity of gravity anchor,this paper designed two groups of indoor scale model tests on non-rock-socketed and rock-socketed gravity anchors with a scale of 1∶50 to discuss the bearing capacity and load distribution of different models under a combination of vertical loads and horizontal loads,finally obtaining the effectiveness of rock socketed effect.The test results show that the gravity anchor considering rock socketed effect exhibits smaller displacement under the same horizontal cable force,with the horizontal ultimate failure load increased by 16.7%.Moreover,after the bottom plate is embedded in the moderately weathered layer,higher resistance generated by the bonding between the rock layer and anchor can reduce the stress level of the bottom plate and transform the ultimate failure mode of the gravity anchor from “sliding friction failure mode ” to “overturning failure mode ”.The above results provide technical support for the design and construction of the gravity anchor foundation.
Theoretical and Experimental Studies on Adaptive Spatial Rotating Main Cable Saddle
CHEN Yuanlin, HUANG Anming, CHEN Long, and XIE Jun
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.022
To ensure the accuracy of the main cable alignment during adaptive rotation,an adaptive spatial rotating main cable saddle suitable for spatial suspension bridges was designed.The main cable saddle had two adaptive rotating pair mechanisms with axes passing through the IP point.By using a specific suspension bridge as a case study,the design was validated through a combination of finite element analysis and model testing to assess the reliability and structural safety of the adaptive rotation mechanism.The results show that the adaptive spatial rotating main cable saddle can automatically adjust its orientation based on variations in the main cable load during construction,with self-limiting rotation to ensure safe and controlled movement.The finite element stress analysis results of the fixed main cable saddle are consistent with the measured stress values of the rotating main cable saddle,indicating that the adaptive rotation balances the lateral force generated by the main cable rotation on the saddle.This leads to an improved load distribution on the spatial main cable saddle,ensuring the reliability of the rotation mechanism,and the structure meets the strength requirement.
Research on Mechanical Entry Excavation and Reinforcement Measures for Large Cross-Section Tunnel
LIANG Xiao, LI Ke, GUO Hongyan, HU Xuebing, and YAO Chengrui
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.023
With the innovation of tunnel construction techniques and mechanical equipment,mechanical drilling and blasting for mountain tunnels have gradually developed.However,several challenges exist during the mechanical entry excavation for mountain tunnels,including the significant influence of geological factors,limited equipment adaptability,and constrained working space.This research,based on a specific tunnel project,utilized FLAC3D finite difference software to study the mechanical excavation method and auxiliary reinforcement measures for shallow-buried segments at the large cross-section tunnel portal.A comparative analysis was conducted on the displacement of surrounding rock,the stress of supporting structures,and the variation of plastic zones before and after tunnel face reinforcement for different advances per cycle and faces when employing a micro-step construction method.The findings indicate that without face reinforcement,to ensure construction safety,the mechanical excavation advance in the tunnel portal should be controlled within 1.2 m per cycle,and the overlapping length of the forepoling pipes should be no less than 3 m.When increasing the advance per cycle,tunnel face reinforcement is necessary.With the use of 10-meter-long and 1.5-meter-spaced fiberglass anchors arranged in a honeycomb pattern to reinforce the tunnel face,the maximum advance per cycle can be increased to 1.8 m.
Influence of Train Speed on Thermal Insulation and Anti-Thawing Length for Tunnel in Cold Region
HUANG Huanan, CHEN Yong, WANG Yibo, and WU Yaping
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.024
To study the influence of train speed on thermal insulation and anti-thawing measures for surrounding rock of tunnels in cold regions,it is necessary to analyze the temperature field.By using the Kunlun Mountain Tunnel Project in cold regions as a case study,the effects of external atmospheric temperature,piston wind effects caused by varying train speeds,and the driving resistance on the distribution of the tunnel ’s internal temperature field were considered.A three-dimensional numerical calculation model including the surrounding rock,concrete lining,and tunnel air was established by utilizing the thermo-fluid-structure interaction (TFSI ) technique.The thermal environment variations caused by trains at different speeds were predicted.The result shows that during long-term train operation through the tunnel,both the piston wind speed and the pressure difference between the front and rear of the train increase as the train speed rises.This,along with increased driving resistance,significantly raises the surrounding rock temperature.Regardless of operational duration,the radial temperature impact depth of the surrounding rock decreases with greater tunnel depth,and axial temperature variations are reduced.For long-term train operation at speeds of 80 km/h and 160 km/h,it is recommended to set the thermal insulation and anti-thawing lengths at the two tunnel portals of the Kunlun Mountain Tunnel to 420 m and 790 m,respectively,so as to effectively prevent thaw settlement hazards in the surrounding rock of the Kunlun Mountain Tunnel.
Section Form of Open-Cut Tunnel by Ultra-Large-Diameter Shield Empty-Push Technology
SUN Chao and ZHANG Guangwei
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.025
Based on the engineering background of the open-cut section by the shield machine with overall movement in the rapid transformation project of Wanghai Road,Shenzhen City,the structural stress and economy of three types of section forms under construction and operation conditions were analyzed to determine the optimal section design.The load-structure model was used to analyze the parameters affecting the internal force of the optimal section.The research results show that the top and bottom plates and side walls in the scheme with ribs set at the corner (scheme 3) have uniform force,and force during the construction period is close to that during the operation period.The scheme has the most economic and reasonable structural forms and is the optimal one.Setting uplift piles on the bottom plate solves the problem of anti-floating problem of tunn el structure,reduces the bending moment of the bottom plate,and optimizes the force conditions of the bottom plate.Under constant rib spacing,as the rib size gradually increases,the bending moment of the tunnel top plate support and mid-span position gradually decreases.The length and width of the rib have a more significant impact on the force on the top plate than the thickness of the rib.The optimal rib size is 6 m × 6 m × 1 m.
Smart Road and Intelligent Transportation
Application Research of BIM Technology in Highway Prefabricated Bridge Scheme Design
LI Jinlong, WANG Xinnan, LIU Dongsheng, and CHEN Zhongzhi
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.026
At present,the highway bridge scheme requires continuous adjustments and upgrading due to iterative updates of design data and refined investigation of the surrounding environment of the bridge site.This paper upgraded the traditional route design software,developed a GIS-integrated platform,built a three-dimensional environment with design data as the core,and created a bridge scheme model through parametric intelligent design.It also evaluated and optimized the bridge scheme based on the integration of the bridge model and the surrounding environment.The results show that by using BIM technology,the forward design of a bridge scheme based on a three-dimensional environment is realized.This approach automates the scale statistics of bridge construction,the positioning and identification of high piers,and the transmission of design data to downstream professionals for further use.The bridge scheme design based on BIM technology can significantly improve the design efficiency,enhance the intuitiveness of bridge scheme evaluation,and increase the practical value of design data.
Application of Superelevation Detection Technology in Ship Collision Prevention System of Cross-Sea Bridges
SONG Xiaodong, DUAN Min, REN Quanli, HU Jianan, YANG Naiheng, CHEN Jingwen, and TONG Jianrong
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.027
Cross-sea bridges are an important component of national infrastructure and an important regional transportation hub,which have a significant impact on economic development,regional integration,and cultural exchange.Ship superelevation is an important factor that threatens the safety of bridges.Therefore,superelevation detection is an important means to improve the service level of channel navigation,standardize the navigation order of ships in the water area near the bridge,and enhance the ship collision prevention ability of bridges.This paper conducted theoretical analysis and engineering feasibility research on superelevation detection by using laser alignment,laser ranging,optoelectronic detection,LiDAR detection,and machine vision.According to the superelevation detection requirements of the Hong Kong-Zhuhai-Macao Bridge,two technical routes and equipment,namely machine vision and LiDAR detection,were selected and designed,and real ship testing was conducted.The results show that under the current technical conditions,machine vision can be used for superelevation detection of ships in long-distance and ultra-wide water areas of cross-sea bridges,and the test results can provide effective support for the construction of related projects.
Industrial Design and Economic Analysis of Steel Box Girder Bridge with Conventional Span
CUI Bing and CHEN Kun
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.028
To improve the industrial construction level of steel bridges,a prefabricated continuous steel box girder bridge was designed in this study,which is suitable for bidirectional four lanes and six lanes with spans ranging from 40 m to 80 m.The overall dimensions and local structures of the steel box girder bridge were determined according to the specifications and engineering experience,and the load-bearing capacity was checked.Modular industrial products were designed by defining the vertical and horizontal modular divisions for the steel box girders,resulting in 21 standardized modular components.Based on the concept of life cycle,an economic analysis of the prefabricated steel box girder bridge was carried out.Research results show that the overall dimensions and local structures of the prefabricated steel box girder bridge are reasonable.The modular product design improves the versatility of steel box girder bridges across different spans and lanes,greatly simplifying the construction process to meet industrial construction requirements.When considering the whole life cycle and the recovery of steel materials,the average annual cost of prefabricated steel box girder bridges is only about 30% of that of concrete girder bridges.Additionally,its carbon emissions during the construction phase are lower than those of concrete girder bridges,providing a significant economic advantage over the entire life cycle.
Foreign Highway
Parametric Analysis of Composite Slab with Steel Bar Trusses at Construction Stages
ZHANG Junhao, HE Jun, TAN Chao, FENG Sidong, and WANG Zitong
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.029
To clarify the structural behavior of composite slab with steel bar trusses at key construction stages including hoisting and concrete post-pouring,a composite beam bridge with a main span of 60 m in Georgia ’s E60 Highway was investigated.A finite element model was developed by using ABAQUS to simulate the construction process and analyze the influence of parameters such as prefabricated bottom slab material,number of hoisting points,slab thickness,and number of steel bar trusses on the principal stress of concrete and mid-span deflection.The results indicate that ultra-high-performance concrete (UHPC ) prefabricated bottom slabs prevent plastic damage and enhance slab stiffness.Normal concrete (NC) prefabricated bottom slabs should set six or more hoisting points,while UHPC prefabricated bottom slabs require only four hoisting points.Increasing slab thickness can raise the concrete ’s maximum principal stress at the hoisting stage,but it has a negligible impact at the concrete post-pouring stage.Increasing the number of steel bar trusses in the prefabricated bottom slabs can reduce the concrete ’s maximum principal stress at the hoisting stage,and both the concrete ’s maximum principal stress and mid-span deflection decrease at the concrete post-pouring stage with the increase in the number of steel bar trusses.These research findings may provide a reference for the hoisting and concrete post-pouring of composite slabs with steel bar trusses and support the actual application of UHPC-NC composite slabs.
Design and Simulation Evaluation of Converged Toll Collection Schemes for Senegalese Highways
LAI Zengcheng, ZHANG Ning, YANG Shichun, DING Xueqi, and JI Yanjie
Date posted: 2-22-2025
DOI: https://doi.org/10.14048/j.issn.1671-2579.2025.01.030
The Senegalese highway toll collection system is inefficient,and significant congestion and delays frequently occur at toll stations in the face of sudden traffic surges during holidays.This paper examined the limitations of the existing toll collection methods on Senegalese highways and combined the image detection algorithm and electronic license plate recognition technology with the existing MTC and ETC toll collection methods to construct a converged toll collection method based on vehicle information recognition.The paper aimed to optimize the Senegalese highway toll collection system,reduce its cost of use,and improve the efficiency of toll collection.The BPV Thiès toll station in Senegal was selected as an example,and experimental simulation was carried out for different deployment schemes.The results show that compared with the existing toll collection method,the inbound delay during peak hours can be reduced by 34.99% and 62.49%,and the outbound delay can be reduced by 38.01% and 62.44%,respectively.By increasing the ETC penetration rate to 50%,the converged toll collection scheme further reduces the average inbound and outbound delays by 80.57% and 79.64%,respectively.This demonstrates that the converged toll collection technology can markedly enhance toll collection efficiency and serves as a pragmatic reference for highway toll collection methods in Senegal.
