In this paper,being relied on the project of strengthening the soft soil of a bridge abutment with high-pressure rotary jet grouting piles at a highway in Guangdong,with continuous8 yearsof settlement monitoringbeing carried out,the impact of factors such as pile spacing and diameter on the reinforcement effect of high-pressure rotary jet grouting piles has beenanalyzed.Analysis on site monitoring has shown that the overall settlement of the soft soil after treatment with high-pressure rotary jet grouting piles decreases over time,and the settlement generated in the first three years accounts for approximately 45～70%of the total settlement during the monitoring period.When the thickness of the soft soil layer does not change much along the longitudinal direction,choosing a conventional pile spacing can better control the settlement of the soft soil compared with using large spacing.The design of high-pressure rotary jet grouting piles in soft soil of the bridge abutment based on the concept of variable stiffness design of pile is beneficial for reducing the impact of longitudinal uneven settlement of the embankment.
Being based on Zhong-jiang Expressway Reconstruction and Expansion Project,the applicability and economic viability of deep soil treatment schemes of embankment and bridge plans have been discussed.The selection criteria for embankment and bridge plans under different road sections and fill heightshas been summed up,and the correlation curve between the length of the selected road section and the cost per square meter of the soft foundation treatment schemehas been compared.Considering on-situ construction conditions,the optimal selection of soft foundation treatment and bridge plans has been made and validated through examples.
According to the actual situation of the project,inthis paper,the finite element software has beenadoptedto analyze the slope stability,deformation and force of the support scheme of the high cutting slope,and on this basis,the optimization analysis on the pile spacinghas been carried out,the position ofeffective plastic zone has beendetermined,and it has been concluded that the change of the horizontal displacement of the pile body is a"7"shape deformation,the horizontal displacement value of the pile top is 13.5mm,and the maximum horizontal displacement value is 15.3mm.At the same time,by comparing and analyzing the two working conditions of whether to apply the anchor cable,it has beenshown that the prestressed anchor cable is not only conducive to reducing the shear force and bending moment value of the pile body,but also to the uniform distribution of the shear force value and bending moment value of the pile body.Finally,the stability of the slope under different pile spacing conditions has been analyzed,and it has beenobtained that the reasonable pile spacing is 4.5m.
Account settlement has become an important part of cost management in expressway construction projects.In response to current problems of long cycles and low efficiency in highway projects,in this article,takingHuazhan Section of Yunzhan Expressway as an example,accountsettlement has been deeply explored and analyzedfrom the perspective of construction management,corresponding management measures and practices have been pointed out,the efficiency of accountsettlement of the project has been improved,whichhas acceleratedcapitalturnover of contractors,solved the problem of long delays in accountsettlement after completion of the project,and couldprovide reference for similar projects.
The subgrade resilient modulus is a basic parameter of highway pavement structure design,which is usually obtained by bearing-plate method.Being based on Qing-hua Expressway Project,with Visual Studio.net as the development platform and Excel as the data warehouse,through analysis on the engineering characteristics of Qing-hua Expressway and testing principle of subgrade resilient modulus,a data collection and analysis system of highway subgrade resilient modulus has been developed.The test results of the system have shown that the programming of the test solution process of subgrade resilient modulus(bearing-plate method)can effectively overcome the shortage of manual recording and analysis that cannot detect the validity of the data in time,and help perceive the problems in the test process in time,so as to ensure that the test could be completed efficiently and accurately.At the same time,the data such as the modulus of resilience of soil foundation at different test points have beenstored in one system,which canhelp technicians to have a more comprehensive grasp of the technical status of the subgrade under construction,and canalso provide basic data for subsequent road maintenance.Engineering practice has shown that the application of information technology in road engineering can greatly reduce work intensity and error probability of technicians,thereby improving work efficiency.
Cable-stayed slab bridge is a special form of bridge structure,which forms a statically indeterminate structural system by wrapping the cable-stayed cables inside the concrete cable-stayed slab,forming an organic fusion of three main components:the main beam,bridge tower and cable-stayed slab.In this article,taking the representative PanyuShaxi Bridge(2-span 60m cable-stayed slab bridge)as the research object,being based on the establishment of a spatial finite element model for theoretical analysis,a comparative analysis has been conducted through actual vehicle load tests and comparisonwithcompletion inspection test results,the structural stress characteristics and working state of the bridge structurehave been deeply explored.Research has found that the Shaxi Bridge is in an elastic working state,and the bridge structure has good dynamic characteristics,but the structural stiffness has decreased.In addition,in this article,the diseases of cable-stayed slab bridgeshave also been investigated and organized,the causes of bridge diseases based on load test resultshave beenanalyzed,and targeted maintenance and repair strategieshave been proposed.The analysis methods and some conclusions of this study have certain practical value and can provide reference for the maintenance and management of similar bridges.
Being based on Guangzhou-Shenzhen Expressway Reconstruction and Expansion Project,analysis has beenfocused on the significant challenges faced in the design of expressway reconstruction and expansion,and a comprehensive BIM(Building Information Modeling)technology application process tailored to such projectshas beenproposed.Detailed modeling methods for various disciplines involved in the reconstruction and expansion projecthave beenpresented,including environmental modeling,existing highway modeling,reconstruction and expansion highwaymodeling,and underground pipeline modeling.Additionally,in the study,the application of BIM technology in several key aspectshas been discussed,such as BIM 3D digital sandbox,assisted design and alternative selection,panoramic display of design schemes,visualization of traffic organization simulation,and construction simulation.These applications have demonstrated the effectiveness of BIM technology in the surveying and design phases of expressway reconstruction and expansion projects,providing valuable references for similar projects.
The reconstruction and expansion project of Xinxin Highway is a section of Provincial Highway S118,which is an important passage between Xintang and Zhongxin,two important economic towns in Zengcheng District,Guangzhou.There are a total of 5 steel box girder pedestrian bridgesto be built in this project.Due to high traffic volume of this section and the principle of opening to traffic while construction is being carried out,the pedestrian bridge cannot be constructedwithclosed traffic.In order to ensure the construction progress,quality and safety of the pedestrian overpassbridges,the original design has been divided into 5 segments that have beenmanufactured in the factory and transported to the lifting position under the pedestrian overpass bridgeusing temporary support piers for lifting and splicing.The optimization hasbeendetermined to divide them into two segments that have beenmanufactured in the factory with pre-camber before being transported to the lifting position under the pedestrian overpass bridgeusing temporary support piers for lifting and splicing.By optimizing the processing and assembly plan,the construction progress of pedestrian overpasses has been accelerated,the number of welding seams on the construction site have been reduced,the impact of external adverse factors on the welding of steel box beams has been reduced,the construction time of assembly and road occupation has been shortened,and traffic safety has been ensured.
In order to supplement the risk assessment system of steel shell concrete immersed tunnel construction in our country,the risk assessment method of FAHP-cloud model based on optimized LEC method has been used to identify and analyze the construction risk of steel shell concrete immersed tunnel.The construction structure model of steel shell concrete immersed tunnel has been established by AHP method,and the weight of each index has been determined by fuzzy analytic hierarchy process.Adopting the optimized LEC method to calculate the risk level of the risk source at the index level,using MATLAB cloud model to determine the expected value of the risk level,the overall risk grade of steel shell concrete immersed tunnel has been determined based on fuzzy analytic hierarchy process(FAHP).The feasibility of this method has been demonstrated by the application of the evaluation model to the case study of immersed tunnel in Shenzhen-Zhongshan Bridge Project.
In order to improve the anti-overturning ability of continuous curved box girder bridge withsingle-column pier and ensure the safety of bridge structure under the action of heavy-load vehicles.According tocurrent bridge design specifications and technical requirements of the industry management department,the overturning failure mechanism of continuous curved box girder bridge withsingle-column pier under heavy-load vehicles has been studied,the contents,key points and reinforcement methods of the anti-overturning performance evaluation of such bridges have been summed up.Being combined with the spatial layout and structural stress characteristics of the bridge in the engineering example,the reinforcement scheme of adding cover beam and support for single column pier or changing single column pier into multi-column pier has been proposed.The anti-overturning evaluation model of continuous curved box girder bridge with single column pier before and after reinforcement has been established by beam element,and the anti-overturning performance of the bridge under each reinforcement scheme has been compared and analyzed.The results have shown that the reinforcement method of changing single-column pier into multi-columns pier can more effectively improve the anti-overturning stability of the bridge.The anti-overturning stability coefficient of the bridge under eccentric load on both sides after reinforcement is 1.73 and 1.48 times that before reinforcement.The technical analysis method adopted in this paper can provide reference for anti-overturning evaluation and reinforcement of similar bridges.
In this paper,the impact of shield construction on deep foundation in normally consolidated soil has been studied,the law of horizontal displacement and deformation of soil under different soil parameters,loss rate,different buried depth and different distance of tunnel excavation boundary has been studied and analyzed,based on the relationship between the depth displacement at different positions and the radial compression of the tunnel,the prediction model of soil displacement induced by shield tunneling has been established,this model makes up the defect that the usual Winkler elastic foundation beam model does not consider the shear resistance and spatial effect of foundation soil.In addition,a simplified foundation beam model has been established based on the prediction model,and the validity of the model is verified by comparing with the theoretical analysis data and the actual engineering data,it can provide a simple calculation method for the analysis and calculation of the pile foundation construction of the bridge adjacent to the shield machine,and provide a basis for the adoption of pile foundation protection measures.
To improve the accuracy of weather recognition in expressway images and achieve timely warning for severe weather,a weather image recognition algorithm based on ensemble learning strategy has been proposed.The algorithm uses DenseNet121 for the five-classification recognition of weather images,ResNet-18 for re-recognition of categories that are prone to confusion between clear and cloudy conditions,and finally,ResNet-18+MS-Loss for decision fusion.Experimental results have shown that the weather image recognition model based on ensemble learning strategy can effectively solve the problems of insufficient training samples and low accuracy,and canachieve good results in improving weather image recognition,achieving recognition of five types of weather:clear,cloudy,rainy,foggy and snowy.
The diseases of the external surface coating of steel-box-girder structure,such as aging,corrosion and cracking,havebeen the important impact factors of the safety and durability for bridge structure.The periodic inspection of the diseases has become a very important work during the operation period of bridge structures.Previously,the external surface of steel-box girder disease detection mainly adopted manual inspection method.However,for the sea-crossing bridges with many steel-box girders,the manual inspection has a lot of workwhich will take too long time,and there are some problems of poor detection accessibility and safety hazards,the work quality will gradually become unstable.In response to this,as for Hong Kong-Zhuhai-Macao Bridge,beingrelied on the national key research and development project"Integrated Application of Intelligent Operation and Maintenance Technology of Hong Kong-Zhuhai-Macao Bridge",intelligent inspection robots for disease detection on the external surface of steel-box girdershave been developed,in order to improve the detection efficiency and the continuous stability of inspection quality.In this paper,the intelligent detection technology and application effect of the steel-box-girder intelligent detection system of Hong Kong-Zhuhai-Macao bridgehave beenanalyzed,in order to provide reference for similar engineering inspection and operation.
Video event detection technology has been widely used in highways,on this basis,by analyzing the actual application effect of video event detection system in the complicated environmental conditions of multi-tunnels group,system optimization suggestions have been put forward for the distinctive characteristics of truck types,large traffic,high frequency of motorcycles on the road and diversified tunnel environment,so as to improve the resilience and detection ability of video event detection technology in different application scenarios and environments.
随着我国交通基础设施建设的快速发展,高速公路改扩建工程已成为高速公路建设的重要组成部分.为了提高改扩建工程的安全管理水平,结合中江高速公路改扩建工程进行了安全知识管理系统的开发应用.首先,通过分析高速公路改扩建工程的安全特点和知识需求,构建了基于安全知识管理理论的知识体系框架.其次,以先进的安全知识管理技术为基础,设计了中江高速公路改扩建工程安全知识管理系统,并介绍了系统功能、架构和关键技术.最后,通过对系统的实际应用效果进行分析,验证了安全知识管理系统在提高改扩建工程安全管理水平方面的显著作用.
粤港澳大湾区作为我国最开放、经济最活跃的地区之一,交通发展已进入网络化、立体化、多模式化的新阶段,城市交通规划设计、建设决策、运营管理等如何实现区域级大范围的量化分析,科学化、精细化地评估规划决策是迫切的需求.针对省内既有模型技术架构不够完善、基础数据更新不及时、核心参数缺少标定、精细化评估分析应用相对不足等问题,结合未来湾区时空格局重构及出行规律、模式演变等发展转变,提出构建基于数据驱动的新一代区域综合交通模型体系方法,重点推进区域模型技术架构优化升级、模型数据库搭建更新、模型核心参数标定校核及模型应用测试等关键技术研究.
钢桥面板疲劳问题是目前钢桥研究的热点课题之一,其中面板纵肋连接细节是钢桥面板危害较严重的疲劳细节.铺装层与面板共同受力决定面板纵肋连接细节的疲劳应力.为分析铺装层对该细节的影响,以国内某大跨度钢桥为对象,建立了疲劳分析有限元模型.计算结果表明:当钢桥面板厚度为16mm时,考虑铺装层受力后,面板纵肋连接细节最大疲劳应力幅由45.3MPa降低至36.7MPa.不同季节造成的铺装层刚度变化对该细节疲劳性能的影响不能忽略.
涎流冰是川藏交通廊道区普遍存在的一种地质灾害.通过卫星图像判识和现场调查表明,川藏公路涎流冰以坡面溢流型为主.通过室内模拟试验分析了地形、透水层厚度、含水层厚度及渗透性等对涎流冰形成的影响.试验分析表明,负温条件下当地下水出露或地下水浅埋(一般地下水位小于冻深)时涎流冰就会形成.负地形因利于地下水汇集而更易于形成涎流冰.涎流冰形成过程中,孔隙水压力的变化具有明显的阶段性.冻结过程中冻结层逐渐封闭为整体,孔隙水压力呈先线性增长、后增长速率逐渐变缓直至稳定.地下水位越深,冻结形成涎流冰的时间越长;孔隙水压力越大,间接说明涎流冰的形成与冻深有关.含水层渗透性越好,相同条件下形成涎流冰的时间越短,形成的涎流冰规模越大,地下水孔隙水压力越高.含水层厚度越大,涎流冰规模也越大,但地下水孔隙水压力相对降低.试验结果表明,负地形、地下水浅埋、含水层厚且渗透性好,是形成大规模涎流冰的有利条件.
高应变法是一种对单桩竖向抗压承载力和桩身完整性进行判定的检测方法.灌注桩的高应变检测,被检桩的混凝土龄期应达到28d或强度达到设计要求,而管桩也应满足不同土层对应的休止时间的要求.分析了预制管桩不同休止时间的承载力变化,在承载力-时间曲线中寻找规律,以满足部分特殊施工工艺的工期要求,为设计及施工提供相关依据.
探讨编制工程建设项目档案工作规划的必要性、方法与意义,介绍其在项目档案工作中规范管理、提高效率和保障安全等方面的作用.通过文献研究分析与项目实践总结,归纳出编制档案工作规划的关键要素.在具体的编制内容方面,档案工作规划需要涵盖诸如明确组织职责、制定收集整编计划、建立监督考核机制等关键要素.编制过程中需严格遵循相关法律法规,全面考虑具体项目的特点以及合理的分工.
