Abstract:In order to fully utilize expansive soil as filler in highway reconstruction and expansion projects，this paper draws on the successful experience of using expansive soil directly in road construction.It proposes an embankment treatment scheme that involves the use of geogrid-reinforced expansive soil with edge wrapping，based on the reconstruction and expansion project of the Hefei to Dagudian section of the G 40 Shanghai-Shaanxi Expressway.Through laboratory tests，the road performance and swelling characteristics of the expansive soil filler were investigated to determine the applicable scope and compaction control indices of the filler.Then，the feasibility of the embankment treatment scheme was demonstrated through the prediction of the embankment swelling，stability analysis of geogrid-reinforced slopes，and economic effect analysis.The results show that the total swelling-shrinkage ratio of the filler is 1.12%，and its RCBR is greater than 3%，preliminarily verifying the feasibility of using physically treated expansive soil filler，such as edge wrapping and reinforcement，as lower embankment material.If the compaction control index determined by the wet compaction test is used，the estimated value of the embankment swelling will be an order of magnitude smaller than that determined by the dry compaction method.The anti-pullout safety factors of the geogrids at each layer meet the standard requirements of not less than 2.0，avoiding the risk of pullout.Compared to the lime improvement scheme，this scheme can significantly shorten the construction period and reduce costs.

Abstract:Highway construction in desert areas is of great significance to improving the nodes of transportation networks and developing the economy of remote areas.In order to effectively explore the construction risks of desert highway subgrade engineering，the five aspects of personnel risk，technical risk，material risk，mechanical risk，and environmental risk were analyzed，and 23 indicators affecting the construction risk of desert highway subgrade engineering were screened out by literature research method.Based on the effective data collected by questionnaire survey，a structural equation model （SEM ） of the construction risk of desert highway subgrade engineering was constructed，and the key influencing factors of the construction risk were analyzed.The results show that the construction risk of desert highway subgrade engineering is mainly affected by bad weather，violations of personnel in three aspects，quality of aeolian sand，mechanical repair and maintenance，and technical integrity.Targeted control measures are also proposed to provide a reference for the sustainable development of desert highways.

Abstract:In order to solve the differential settlement of soft subgrade in coastal areas，based on the elastic deformation theory of overconsolidation stress ratio，the calculation and analysis of artificial overconsolidation stress ratio and the new technology of lightweight replacement were carried out to reduce the additional stress of vehicle load and structure weigh.The results show that the replacement thickness of the lightweight material with suitable density can make the additional stress at the bottom of the subgrade less than the deadweight stress of the original soft soil，and the additional stress is less than the initial flow stress of the soft soil.The resulting overconsolidation stress ratio can put the soft soil in a state of elastic deformation.The observed data of settlement performance of the test road show that the settlement of the pavement structure remains with lightweight replacement is stable at about 1 mm one year after construction；the settlement of conventional pavement structure reaches 17 mm，which exceeds the upper limit of driving comfort of 15 mm，and the settlement is still intensifying.The proposed lightweight replacement technology based on the artificial overconsolidation stress ratio theory can effectively solve the differential settlement of soft subgrade，which has significant theoretical value and practical application prospects.

Abstract:In order to study the stress characterist ics of water film on cement concrete road surface under the action of the tire and the influence of grooves，the finite element model of tire-water film-road surface was constructed using SolidWorks and Ansys Workbench.Based on computational fluid dynamics （CFD ） control equation and fluid-structure coupling theory，the flow law of water film on road surface under the action of the tire and the influence of water film thickness，driving speed，groove width，groove spacing，and groove direction on the hydrodynamic lift of tire were analyzed.The results show that the hydrodynamic lift of the tire increases with the increasing water film thickness.The hydrodynamic lift increases obviously as the water film thickness exceeds the tread depth of the tire.The hydrodynamic lift of the tire can be reduced effectively by increasing the groove width and decreasing the groove spacing.The drainage performance of transverse pavement grooves is better than that of longitudinal pavement grooves under the same groove parameters，and the effect of the former in reducing the hydrodynamic lift is better.

Abstract:The existing design specifications do not make special design provisions for pavements in long and large longitudinal slopes，and the directly applied design specifications ignore the stress characteristics of these pavements，which fail to guarantee pavement performance and life.In order to realize the differential design of the pavement structure of special road sections，based on the measured dynamic modulus of asphalt mixture，annual traffic volume，and temperature data，this paper used the self-developed temperature-axle load analysis software to convert the real traffic volume into standard axle load.Abaqus software was used to establish a rut model under the coupling effect of measured axle load and temperature，and the influence of long and large longitudinal slopes on rut development law was analyzed.The results show that the increase in slope leads to a decrease in speed，which easily causes rut disease of asphalt pavements in long and large longitudinal slopes.Based on the rut equivalence principle，the correction factor of axle load conversion under different slopes and slope lengths is proposed，which provides a theoretical basis for the differential design of asphalt pavements in long and large longitudinal slopes.

Abstract:The interlayer bonding state of pavement structures changes due to the influence of various factors under service conditions，and this change exhibits a significant influence on the mechanical behavior of pavement structures.Through the composite structure test and numerical analysis，the mechanical behavior of the composite structure of different wearing courses and underlying layers under different stresses and bonding states was studied.The test used three commonly used wearing course （surface layer ） materials of asphalt pavements，namely AC- 13，OGFC- 13，and SMA- 13 for comparative analysis.The test results show that different composite structures exhibit different interlayer bonding properties and fatigue characteristics due to the difference in material properties.Compared with the composite structure of AC- 13 + AC- 20，OGFC- 13 + AC-20 and SMA- 13 + AC- 20 have stronger shear fatigue resistance but weaker flexural and tensile fatigue resistance.The interlayer compression-shear failure mainly occurs at the interlayer interface and the interfacial transition zone.The compression of the void structure of the material and the interlocking deformation of the bonding interface can be observed.The local interface will have the aggregate destroyed during the extrusion and shear process，accompanied by shear deformation and slippage of the interface.The fatigue failure behavior of composite structures under flexural and tensile stress is obviously different from that under compression and shear stress.The difference in material properties has a significant effect on its flexural and tensile deformation resistance，and the fatigue failure mode is affected by interlayer bonding and interlocking.With the development of material damage，the cracks develop upward from the bottom of the composite beam specimen along the periphery of the aggregate.When the cracks reach the interlayer interface，they develop laterally along the interface to cause local deadhesion and then develop upward until the failure of the composite structure specimen.

Abstract:Topsoil slide and instability of expansive soil slopes may occur under variable saturation conditions.In order to study the strength characteristics of unsaturated expansive soil under low stress conditions，several different matrix suction and stress conditions were set by unsaturated triaxial apparatus.The triaxial shear test of Hefei expansive soil was carried out，and the test data were analyzed.The test results show that when the net confining stress on the expansive soil continues to weaken，the stress-strain curve transitions from strain hardening to strain softening.The strength of unsaturated expansive soil increases with increasing matrix suction.The shear strength of shallow expansive soil shows a significant reduction with non-linear characteristics.The cohesion of unsaturated expansive soils has a significant effect on the shear strength.The cohesion decreases significantly under low stress conditions，and the internal friction angle increases significantly.The net confining stress significantly affects the strength of the soil at the low stress level，but matrix suction has a weak effect on the strength of the soil at the low stress level.

Abstract:The orthogonal design t est was used to quantitatively analyze the influencing factors and influence degree of compressive strength，shear strength index，and permeability coefficient of improved loess，and the optimal content of improved loess was obtained.In addition，the improvement mechanism of nano-clay materials on loess was explored by scanning electron microscopy.The results show that：① The factors affecting the compressive strength of improved loess are the content of nano-clay，water content，and curing age，and the factors affecting cohesion，internal friction angle，and permeability coefficient are the content，dry density，and confining pressure.② Under different influencing factors，nano-montmorillonite can effectively improve the compressive strength of loess than attapulgite.③ When the material content is less than or equal to 1%，the shear strength index of improved loess by attapulgite is generally higher than that by nano-montmorillonite，and the permeability coefficient is opposite.However，when the material content is greater than or equal to 2%，the situation is different.④ When the attapulgite content is 1%，and the nano-montmorillonite content is 2%，the surface of the improved loess is the densest，and the porosity is the smallest.

Abstract:Warm recycling technology is an effective new technology for recycling recycled asphalt pavement （RAP ）.In order to improve the pavement performance of warm recycled asphalt and effectively enhance the recycling rate of RAP，the influence of RAP content on the performance of warm recycled asphalt mixture was investigated through mechanical properties and pavement performance analysis，and the correlation between dynamic stability and mechanical parameters of creep tests under repeated loading was discussed.The results show that with the increase in RAP content，the high-temperature stability，shear resistance，and elastic deformation resistance of warm recycled asphalt mixture are improved，but the low-temperature crack resistance and water stability are decreased.In addition，there is a good linear correlation between the flow number and the dynamic stability，and the flow number can be used to evaluate the high-temperature rut resistance of the mixture.Under the same RAP content，the performance of the modified warm recycled asphalt mixture is superior to that of the ordinary warm recycled asphalt mixture.When the RAP content reaches 70%，the performance of the mixture can still meet the specification requirements，which provides a basis for later engineering application and quality control.

Abstract:The insufficient storage performance of emulsified asphalt has always been a problem affecting its application，and there have been studies in China on nano-SiO2 particles as additives to improve the stability of emulsified asphalt，but the effect is not obvious.Based on the principle of Pickering emulsion，nano-SiO2 with surface modification was used as an emulsifier to directly emulsify matrix asphalt，and whether its stability improvement effect on emulsified asphalt is better than nano-SiO2 as a modified additive was explored.Firstly，three emulsified asphalt were prepared，namely ordinary modified emulsified asphalt A，emulsified asphalt B with nano-SiO2 as a modified additive，and emulsified asphalt C based on the new nano-SiO2 Pickering emulsion emulsification.Then，through optical microscopy and SEM，the microscopic morphological differences of the surface structure of the emulsified asphalt with nano-SiO2 particles as emulsifiers and modified additives were explored，and the different morphologies of emulsion particles in three emulsified asphalt were analyzed.Finally，the indoor emulsified asphalt test and particle size analysis of emulsion particles demonstrated the difference between nano-SiO2 as an emulsifier and a modified additive for the storage stability of emulsified asphalt and the mechanism of difference.Both microscopic and macroscopic experiments have shown that nano-SiO2 as an emulsifier can make emulsified asphalt have better stability compared with nano-SiO2 as a modified additive.The research indicates that nano-SiO2 as an emulsifier can better solve the problem of insufficient stability of emulsified asphalt and has good application prospects.

Abstract:The wheel sticking-free emulsified asphalt is a key material to solve the wheel sticking problem in the process of asphalt pavement construction，with the wheel sticking-free effect as the core index.The accurate evaluation of the wheel sticking-free effect is important for the popularization and application of wheel sticking-free emulsified asphalt.Based on the research results in China and abroad，two test methods for wheel sticking-free effects （counterweight method and indenter method ） were innovatively proposed，and the wheel sticking-free effects of various emulsified asphalt were evaluated.The test results show that the two test methods can accurately evaluate the wheel sticking-free performance of emulsified asphalt，and the test results are in good agreement.Specifically，the counterweight method is suitable for rapid evaluation on construction sites，and the indenter method is suitable for scientific research，testing，and analysis.The two test methods require simple equipment and convenient operations，and they are suitable for the evaluation of wheel sticking-free effects of wheel sticking-free emulsified asphalt in various scenes such as construction sites and indoor research.

Abstract:During the preparation of the recycled asphalt mixture，part of the aged asphalt is first transferred from the surface of the recycled material to the new aggregate and then diffused and fused with the new asphalt，in which the percentage of transferred aged asphalt plays a key role in the final regeneration effect.In order to study the degree of transfer of aged asphalt in reclaimed asphalt pavement （RAP ），the mobilization rate （RMR） was calculated and analyzed based on the Fourier transform infrared spectroscopy （FTIR ）.The AC-13 graded recycled asphalt mixture was mixed and sieved to separate the new aggregate and RAP.The recycled asphalt was extracted，and its carboxyl index （ICI） was determined by FTIR.The RMR was calculated according to the equation.In addition，the influences of RAP temperature，mixing time，and regenerants on the RMR were evaluated.The test results show that the RMR can be increased by 15.5% when the RAP temperature is raised from 135 ° C to 160 ° C.When the mixing time is extended from 90 s to 180 s，the RMR can be increased by 17%.The addition of regenerants can improve the RMR，and the effect of regenerants for warm mix is better than regenerant for hot mix.

Abstract:In view of the shortage of deter mining the optimal foaming parameters of foamed asphalt only by experience，this paper adopted digital image processing technology to collect images of the mixture of foamed asphalt and milled material RAI obtained under different foaming conditions and carried out grayscale image conversion，morphological processing，binary image conversion，and image segmentation，so as to calculate the asphalt wrapping rate in different areas.With the uniform dispersion of asphalt in the mixture as the indicator，the foaming effect of foamed asphalt was evaluated，and the optimal foaming parameters were determined.The results show that the digital image processing technology can quickly and effectively evaluate the uniform dispersion effect of the foamed asphalt，and the accurate value can be calculated as the basis for judging the optimal foaming parameters.The technology has the advantages of simple and quick operation，and it is easy to implement.

Abstract:Prefabricated steel-UHPC composite bridge deck is a new deck structure system that places the longitudinal rib at the upper layer and forms PBL shear connectors.This structure can be prefabricated in the factory and assembled on-site.The adjacent steel beams are integrated by welding，and the cast in-situ UHPC wet joints connect the adjacent UHPC bridge decks.However，these wet joints represent the structure's vulnerable segments but with little research.To this end，a full-scale model test has been conducted to study the flexural behavior of the wet joints in a steel-UHPC composite bridge deck in a practical project.The Abaqus finite element model was established and verified based on the test results.With experimental validation，the parameters analysis of the finite element model，including the wet-joint simulation method，steel panel thickness，UHPC thickness，and inclination angle of the dovetail tenon，were analyzed.In comparing the stiffness calculation equation within the American Society of Civil Engineers （ASCE ），Building Code Requirements for Structural Concrete （ACI），and the Chinese Code GB 50010 —2010，it is discerned that the calculated values in the Chinese code are closer to the test values.Based on the flexural stiffness calculation equation for ordinary reinforced concrete beams，the corresponding parameters are modified according to the test data，and the theoretical r esults are verified with the finite element results.The results show that the wet joints of the steel-UHPC composite bridge deck have excellent ductility and stiffness.Using friction behavior to simulate a wet joint interface has low calculation costs and well-agreed results.Increasing the thickness of the steel panel or UHPC can effectively enhance the stiffness and bearing capacity of the structure.In contrast，the impact of the inclination angle of the dovetail tenon on the structure's stiffness and bearing capacity is minimal.After parameter modification，the modified calculation equation of flexural stiffness can more accurately predict the mid-span deflection compared with the results by ordinary concrete specification.

Abstract:In order to solve the problem of continuous downward deflection of the main girder for a concrete cable-stayed bridge during its service life，the deflection variation of the main girder for a long-span concrete cable-stayed bridge during its service was analyzed based on the modified model.A dual-objective optimization problem was constructed by using the combined static and dynamic finite element model modification method and was solved by the non-dominated sorting genetic algorithm （NSGA- Ⅱ）.The Pareto optimal solution set was obtained，and the coordinated optimal solution was found in the Pareto optimal solution set，so as to modify the finite element model.The calculated values of static displacement and natural frequency of vibration were in good agreement with the measured values after model modification，which can appropriately reflect the actual working state of the structure.On this basis，the influence of time-varying factors such as creep mode and cable relaxation effect on main girder alignment was analyzed by referring to the monitoring data over the years.The results show that the deflection calculated by CEB-FIP 2010 creep mode is closer to the actual deflection.The largest downward deflection is located in the middle span of the bridge，which is about 270 mm after 20 years of service.In the first five years，the average growth rate of the mid-span deflection of the main girder is 33 mm per year，and the total deflection in the first five years accounts for about 50% of that in the first 40 years.The downward deflection of the main girder tends to be gentle in the later period.

Abstract:The development of the transportation an d tourism industry has led to bridges fulfilling additional roles，such as tourism，alongside their transportation functions，resulting in significant changes in structural aerodynamic shape and ventilation rate.This paper analyzed a double-tower single-span steel truss suspension bridge with a main span of 1 088 m，re-evaluated its wind resistance performance through the full-bridge aeroelastic model wind tunnel test，and evaluated the pedestrian comfort problem while studying the wind-resistant stability of the structure.The results indicate that the structural dynamic characteristics of the bridge remain almost unchanged before and after altering the aerodynamic shape of the bridge for its scenic spot function，with no aerodynamic instabilities like vortex-induced vibration or flutter.After changing the aerodynamic shape，there is a noticeable increase in both lateral and vertical static-wind displacement responses，with a certain difference between the two in the torsional direction，whereas no clear pattern emerges.The change in the aerodynamic shape of the bridge，designed around a scenic spot，results in a decreased vertical buffeting response，while the lateral and torsional buffeting responses show a significant increase.After calculation，the structural comfort meets design requirements.

Abstract:Corrugated steel box culverts exhibit a higher section utilization rate compared with circular，arched，and pipe-arch corrugated steel structures，making them more suitable for for scenarios with restricted embankment height.While numerous studies focus on strengthening strategies for corrugated steel box culverts，research on selecting cross-sectional forms is scarce.This study utilized the finite element analysis software Abaqus to develop finite element models of corrugated steel box culverts with sidewall inclination angles of 0°，5°，10°，15° and 20° respectively.The impact of these inclination angles on the structural stress and deformation outcomes was analyzed.The results indicate that increasing the sidewall inclination angles can effectively reduce vertical deformation and maximum stress within the structure.Selecting sidewalls with inclination angles ranging between 5° and 10° is recommended to optimize the high section utilization rate of corrugated steel box culverts.

Abstract:Each strand wire of the main cable in the suspension bridge constructed by the AS method is sleeved and anchored on the strand shoes on both banks.The strand shoe transmits the strand force to the anchoring system through the pull rod.The bearing capacity of the strand shoe after the interaction between the strand shoe and the wires of the main cable，the stress state of the wires after small curvature bending，and the influence of installation accuracy of the pull rod on the anchoring reliability all need to be qualitatively and quantitatively studied and verified by the experiment.In this paper，the main cable suspension bridge constructed by the AS method，namely Yangbaoshan Bridge，was studied，and experimental studies were carried out on the strand shoe and strand under the four working conditions：design load of 6 150 kN in the normal pull rod condition，as well as 0.5° deflection of the pull rod relative to the anchor plate in the horizontal direction，vertical direction，and 45° direction.The results show that the bearing capacity of the strand shoe meets the design requirements.There is no abnormal deformation or damage after the wire bends with a small curvature.The strand shoe and pull rod are connected reliably and have good assembly performance.The spherical washer structure can ensure that the pull rods have an eccentric adjustment ability of about 1°.In order to ensure the design and use requirements of the strand shoe and pull rod are met，it is suggested that the axial installation control precision of pull rods and strands should be maintained within 0.5°.

Abstract:At present，high-strength and high-performance concrete has some disadvantages，such as low flexural strength，large brittleness，and poor volume stability.Reactive powder concrete （RPC ） is a new type of material，which has good mechanical properties and high impermeability.It can reduce the amount of concrete to a greater extent and reduce the weight of the structure，achieving the purpose of safety，reliability，and cost saving.This paper applied RPC to highway prestressed box girder.Through the innovation and optimization of mix ratio，the change in traditional transportation technology，and curing technology research of steam curing shed，it effectively shortens the pouring time of RPC，ensuring the pouring quality and strength.

Abstract:Based on the overpass project over Beijing-Hong Kong-Macao Expressway on Changsha Pan-Pan Road，this paper proposed a construction method of large-slope walking-type incremental launching and high falling beam of steel box girder given the difficulties in busy traffic under the bridge，large pushing slope，and great total height of falling beam.After the steel box girder assembly was completed，some bridge deck ancillary facilities were constructed in advance in the preassembly yard and the weight was allocated.The steel box girder was pushed synchronously，thereby reducing the aerial work on the bridge in the later stage.During the incremental launching construction of the steel box girder above the large-slope approach bridge，the alignment of the steel box girder was adjusted by cyclic grading of the rear fulcrum.When high falling beam was carried out on the temporary pier，the drop beam hanging system was set on the bottom plate of the steel box girder，and the child and mother double circulation mode was adopted.The high falling beam was converted into continuous graded low falling beam by repeatedly “top-down ” method between the crawler shelf pier，the crawler slider，and the replacement pier.By analyzing the elevation matching and constraint conditions of incremental launching and falling beam systems in each process conversion，this paper established the system elevation calculation formula suitable for the general situation and gave a reasonable parameter range.

Abstract:Moraine soils formed during th e Qua ternary glacial period are widely distributed in the west of China，exhibiting good mechanical properties and deep overburden.This paper studied the Dadu River bridge in Luding and investigated the influence of various foundation forms on anchorage stability in the case of considering moraine soils as the soil supporting layer of gravity anchorage foundation through theoretical analysis and numerical simulation.The findings suggest that a slant expanded foundation with a notched sill demonstrates good force-bearing capability and is cost-effective.These results can provide a reference for similar construction projects in the west of China.

Abstract:Near-field earthquakes are more destructive to the continuous rigid frame bridge with high piers and long span.Based on a new-built continuous rigid frame bridge with high piers and long span，considering the seismic demand probability of bridges under near-field earthquakes，this paper utilized OpenSees to analyze the time history of the bridge.The structure response of the bridge under near-field earthquakes was obtained by the nephogram method，and the vulnerability of the bridge under earthquake was analyzed based on the curvature demand probability model of the structure.The results show that the probability response of curvature demand of a continuous rigid frame bridge with high piers and long span is concentrated when the PGA is low，and the probability response of curvature demand is reduced when the PGA is large.Under the action of near-field rare and extremely rare earthquakes，the probability of serious damage and complete failure of bridge piers is almost zero，and the bridge structure can be repaired in medium earthquakes and cannot collapse in strong earthquakes.

Abstract:In the process of highway tunnel construction，the stability of surrounding rock has a great impact on tunnel construction.Therefore，the monitoring measurement and accurate prediction of surrounding rock deformation of highway tunnels are the keys to ensuring the safety of tunnel construction.In view of the low prediction accuracy and poor generalization ability of tunnel surrounding rock deformation，this paper proposed a Bayesian （Bayes ）-based method to optimize the long-term and short-term memory （LSTM ） network.The method first preprocessed the original monitoring data of crown settlement and peripheral convergence，then constructed the initial LSTM model of crown settlement and peripheral convergence of highway tunnels，and used the super parameters in the Bayes optimization model to obtain the prediction results.The model was used to predict the crown settlement and peripheral convergence of a highway tunnel，and the prediction results were compared with convolutional neural network （CNN ） and support vector regression （SVR ） using root mean square error as the evaluation index.When the crown settlement was predicted，the average prediction accuracy of the Bayes-LSTM model was 1.0 and 1.26 higher than that of the CNN and SVR models，respectively.When peripheral convergence was predicted，the average accuracy of the Bayes-LSTM model was 0.3 and 0.32 higher than that of CNN and SVR，respectively.The results show that the Bayes-LSTM model has higher prediction accuracy，and it can judge and choose the historical information in the process of model training，which greatly improves the efficiency of time series data processing.The model provides a new idea for the prediction of surrounding rock deformation of highway tunnels.

Abstract:The rational cross-sectional form of the four-center circular highway tunnel contributes to enhancing the stress state of the lining structure，reducing cracks in the composite lining，and enhancing the durability of the tunnel structure.Utilizing the Ansys APDL programming platform and guided by the design principle of continuous-curvature，a parametric modeling equation for the geometrical dimensions of local tunnel shape in arch foot area was established.The calculation method and numerical simulation models for the equivalent mechanical parameters of the anchor reinforcement area were also developed.The study revealed the impact of the local tunnel shape parameter design in the arch foot area on the internal forces of the lining structure in the four-center circle highway tunnel.It is demonstrated through practical engineering research that radii and lengths of the tunnel's arch foot arc and middle wall arc significantly affect the internal forces of composite lining structure，with increasing the radius of the arch foot arc most prominently restraining plastic zone development in lining structure.It is recommended to prioritize controlling lining tensile stress for local shape optimization to mitigate the risk of lining structure cracking.This approach provides a theoretical basis for the shape optimization of the Pijialing Tunnel，analyzing the sensitivity and influence rules of the extreme values of inner forces on the lining structure concerning the central angle of the middle wall arc （θ2），central angle of arch foot arc （θ3），and the radius of middle wall arc （R2）.

Abstract:In order to eliminate the dust produced by tunnel blasting more quickly and effectively，two kinds of mist spray and dust reduction schemes were put forward，which were the “air duct water mist wrapped type ” and the “vehicle-mounted water mist wrapped type ”.The field test was carried out on Jiaoding Tunnel in Yunnan.The results show that for the dust reduction technology scheme of “air duct water mist wrapped type ”，the dust concentration of the No.1 characteristic position at the tunnel face decreases to 3.87 mg/m3 after 10 minutes of dust reduction，which meets the specification requirements.For the dust reduction technology of “vehicle-mounted water mist wrapped type ”，compared with the initial state without dust reduction，the dust concentration decreases the fastest in the first 20 minutes，and the decreasing amplitude of the dust concentration in the characteristic positions of No.1，No.2，and No.3 after 20 minutes are 70.6%，61.1%，and 89.9%，respectively.Both air duct and vehicle-mounted water mist wrapping technology can achieve corresponding dust reduction effects，with the latter having a more significant effect.

Abstract:This paper took the tunnel-type anchorage on the left bank of a grand bridge over the Qingjiang River as an example and established a three-dimensional geological generalization model based on the engineering geological analysis.In addition，the paper used different software to realize the approximate grid discrete division of complex rock mass and tunnel-type anchorage structure.FLAC3D software was used to simulate different working conditions，and the deformation characteristics and bearing capacity of the tunnel-type anchorage were obtained.It is found that the potential failure mode of the tunnel-type anchorage is that the anchor and the rock mass cut by the structural plane on the upper part of the anchor will slide along the rock/concrete bonding surface at the bottom of the anchor under the tension of the main cable.The adopted research ideas and relevant research results can provide technical support for the practice of tunnel-type anchorage engineering of the grand bridge over the Qingjiang River.At the same time，they help to build a systematic analysis and research method and evaluation index system of tunnel-type anchorage，which is of reference significance for the subsequent construction of tunnel-type anchorage engineering.

Abstract:The strong inter-economic connection makes a spatial correlation between traffic data from multiple related toll stations between urban cluster regions，and an accurate description of this connection can improve the accuracy of expressway traffic flow prediction.However，due to many uncertainties，the correlation is difficult to be captured and quantified.To solve this problem，an ATGCN-ResGRU deep learning-based expressway traffic flow prediction method was proposed.By combining attention mechanisms，three graph convolutional networks （GCN ） topological networks with high，medium，and low attention levels were constructed，and spatial learning data was obtained according to the weighted attention level of each network.The connection of multiple related toll stations was quantified and graded.At the same time，to avoid the over-smoothing problem，two gated recurrent unit （GRU ） modules were connected by residuals to enhance the algorithm's ability to capture time regularity.Finally，a feature fusion layer and a fully connected layer were used to output the predicted values.This algorithm was used to predict the traffic flow at a expressway toll station in Guangdong Province，and the experimental results show that the method proposed in this paper can effectively improve the prediction accuracy.Compared with the classical models of diverse ensemble CNN-LSTM，CNN-BiLSTM，and DL-SVR，the mean absolute error （EMAE） is reduced by 7.95，4.52，and 12.88，and the root means square error （ERMSE） is reduced by 12.03，6.12，and 19.05.

Abstract:To set a reasonable range of the length of the deceleration lane in the diverge area of the left off-ramp for urban underground interchanges，the effects of the length of the deceleration lane，as well as interactions between traffic volumes and design speeds of mainline and ramp on traffic conflict in the diverge area，were exami ned.By taking the underground interchange of the Wuhan East-South Lakes Tunnel Project as an example，the VISSIM micro traffic simulation test was carried out，and the conflict rate （RCR） and exposed time to collision （TTET） were extracted.The results show that ① when the length of the deceleration lane increases，the conflict rate decreases，and the TTET increases in the diverge area；② when the traffic volumes of the mainline or ramp increase，no significant changes were observed in the conflict rate of the diverge area，while the TTET increases to varying degrees；③ when the design speed of the mainline increases，or the design speed of the ramp reduces，both the conflict rate and the TTET of the diverge area increase；④ Analysis of variance and multiple comparisons indicate that the length of the deceleration lane plays a critical role in the variations of conflict rate and TTET，and 120~170 m is generally recommended to be a reasonable length of the deceleration lane in the diverge area of the left off-ramp for underground interchanges.The maximum length should be controlled within 195 m considering the economic value of the project.

Abstract:The safety of waste dump projects of mountainous expressways is related to environmental protection，water and soil conservation，highway building protection，and downstream environment-sensitive point protection，so it is necessary to put forward safety assessment methods.Based on the data analysis of 1 369 waste dumps in Yunnan Province，the safety risk factors of the waste dump engineering were proposed and summarized as five primary indicators，including site selection and design factors，construction factors，regional geological factors，external influencing factors，and data integrity factors，and 18 secondary indicators were further put forward.The group decision-making analytic hierarchy process （AHP ） model was established，and the weight of secondary indexes was determined by 64 technical experts.The technical index system of safety risk assessment of the expressway waste dump engineering was constructed，and the risk classification standard was set.With a waste dump engineering of Dali —Lijiang Expressway as an example，the safety risk assessment system of the waste dump was tested，which proved that the assessment system was simple and easy to implement.The weight optimization needs the support of big data in practice，and the assessment system is suitable for promotion and application in the waste dump engineering of mountainous expressways.

Abstract:Aligned with the peak carbon and neutrality goals，the mechanized construction of roadbed drainage ditches should consider not only construction efficiency and economic factors but also carbon emissions.This study，centered on the Meng-LYU highway，devised approaches to calculate roadbed drainage ditches' carbon emissions and investment costs across three stages：building material production，transportation，and construction.By introducing the concept of carbon trading to align carbon emissions and investment costs，a comprehensive comparison was conducted between the conventional supporting formwork method and the hydraulically powered sliding formwork method regarding equivalent carbon emissions.An orthogonal experiment was conducted involving the upper length of the roadbed drainage ditch，pouring thickness，haul distance，and construction length as key factors.A comparison was made between the equivalent carbon emissions of the two methods，and the influence sensitivity of these factors was analyzed.The research shows that both pouring thickness and construction length have a significant impact on the equivalent carbon emissions of the construction methods.The contribution of equivalent carbon emissions in the material production stage is higher in the traditional formwork，whereas in the material production and construction stages，it is higher for the h ydraulically powered sliding formwork.The hydraulically powered sliding formwork exhibits superior equivalent carbon emissions compared with traditional formwork.The overall decarbonization rate throughout the construction phase is 85.58%.Notably，the equivalent carbon emissions in all stages are lower than those of the traditional supporting formwork，with higher decarbonization rates observed in the construction and transportation stages，reaching 91.92% and 85.06%，respectively.Therefore，choosing the hydraulically powered sliding formwork method for roadbed drainage construction is recommended.

Abstract:With the continuous advancement of China's Belt and Road Initiative，more and more Chinese enterprises are participating in the construction of engineering projects in Central and Eastern Europe，which brings some challenges for designers to master and use local codes for engineering design and consultation.According to the concrete practice of road reconstruction design of Hungary-Serbia Railway （Serbia section ），the application of horizontal and vertical indexes in road geometric design in Serbian was summarized.It is found that road design in Serbian has perfect design standards and systems.The Serbian code and the Chinese code are relatively close in terms of road geometric design standards，and the specification indexes are more limited than the Chinese ones.Its design theory and system pay more attention to the coordination of route，terrain，and environment.In the design，the consistency and continuity of the line shape are emphasized，with a certain degree of flexibility，leaving sufficient design space for the designer.

Abstract:Colombian highway design predominantly adheres to American Standards，emphasizing design concepts reflective of the United States while encompassing Colombia's engineering design habits，concepts，and characteristics.This paper introduced the main design schemes of the Colombia MAR 2 Highway Project in northern Colombia，including protection engineering，drainage engineering，subgrade filling，spoil ground，and pavement.It conducted a comparative analysis between Colombian and Chinese design concepts，highlighting similarities and disparities，and put forward the thinking of mutual learning.