随着中国式城镇化的不断发展,促进城市从粗放式增长向精细化发展.以此为目的,探索城中村改造的方法与路径.以城中村的公共空间更新为切入点,针对城中村更新存在的主要问题,并对存在"缺乏完整空间""破旧闲置""功能复合"等问题的公共空间进行研究.在此基础上,以深圳市福田村为例,研究城中村"功能空间"和"闲置空间"两种不同的类型,揭示了城中村"功能型"和"闲置型"空间再利用的方法.最终提出城中村公共空间的更新策略,为全国其他城中村公共空间改造提供理论基础与科学依据.
悬挂式高层建筑采用外框架和楼层梁分别施工的方法,外框架在逆向累积提升过程中,核心筒和屋顶桁架在日照效应下会影响外框架吊柱的精确定位.以上海金桥国培地块研发项目A塔为研究对象,建立有限元模型,结合上海地区夏季施工计算了日照温差,分析正面日照和45℃角日照两种工况下,累积提升过程中吊柱控制点的位移特征.结果表明,45℃角日照效应对提升框架关键点的变形影响无法满足施工要求.通过采取变形控制措施,计算表明,所有8个提升步中的最后3步结构的拼装应避免在最高温时45℃角日照时进行,其他结构可以全天候施工.
为解决建筑施工过程中的环境污染问题,从污染防治参与方的角度,利用演化博弈理论构建政府、施工企业、社会公众多层次模型,对其进行动态稳定性分析,得到不同条件下各方倾向做出的决策组合,并运用MATLAB对各均衡点进行仿真分析.结果表明,政府策略与其净收益、施工企业和社会公众的行为均有关系,施工企业和社会公众是否选择积极防治污染主要取决于自身的净收益.
The waste fly ash obtained after waste incineration was used in road engineering,which could promote the rational use of resources and the development of green transportation.To study the effect of fly ash on the shrinkage performance of ce-ment-stabilized macadam base material,cement-stabilized macadam with fly ash of 1%,2%,3%and 4%(aggregate mass fraction)was prepared respectively.Thr temperature shrinkage test and dry shrinkage test were carried out.The dry shrinkage strain,dry shrinkage coefficient,temperature shrinkage strain and temperature shrinkage coefficient of cement-stabilized macadam with different fly ash content were obtained.The test results showed that the shrinkage performance of cement-stabilized macadam could be improved with 1%fly ash content.However,with the increase of fly ash content,the temperature shrinkage strain and dry shrinkage strain increase.It was not conducive to the shrinkage deformation resistance of cement-stabilized macadam.
In southwest China,a large amount of solid waste such as tailings,coal gangue,waste rock,coal ash and so on is formed when mining minerals,which not only easily causes geological disasters in mines,but also causes great waste of mineral resources.In response to the national policy of accelerating the construction of ecological civilization and promoting the conser-vation and efficient utilization of mineral resources in the autonomous region,this paper takes Tanggula Mountain section of G109 National Highway as the research site,replaces the original base material with coal gangue and other waste slag,designs different mix ratios,and passes unrestricted compressive strength test,freeze-thaw compressive strength ratio test and erosion resistance test.To explore the feasibility of applying coal gangue to road base in Xizang area.The results show that the com-pressive strength of the base material can be increased and the cumulative brush amount of the specimen can be reduced by re-placing the natural stone with the appropriate amount of coal gangue.With the increase of coal gangue content,the ratio of freeze-thaw strength of the specimens increases on the whole.According to the analysis of the experimental results,the optimal mix ratio is m(cement)∶m(lime)∶m(fly ash)∶m(coal gangue)∶m(crushed stone)=2∶10∶38∶35∶15.
Chengdu-Chongqing high-speed railway is a very important transportation infrastructure in southwest China and has a significant impact on the economy of cities along its route.First,the impact of Chengdu-Chongqing high-speed railroad on the accessibility of major cities along the route is analyzed by constructing a model of weighted average travel time economic poten-tial and a model of average time distance.After that,SPSS 22.0 statistical tool is introduced to establish a linear regression model based on a panel of data for the decade of 2013-2022,and tourism revenue,tourism number,and employment in the tertiary industry are selected as research variables.The impact of Chengdu-Chongqing high-speed railway on the tourism econo-my of cities in the region is empirically analyzed.The study proves that the opening of Chengdu-Chongqing high-speed railway has reduced the average travel time of each city along the route by 45.27%and increased the tourism economic potential of cit-ies along the route by 92%on average,and the opening of high-speed railway has greatly improved the accessibility of cities a-long Chengdu-Chongqing high-speed railway and driven the tourism economy and employment tendency of the tertiary industry in the region.
"Multi-survey integration"is an important innovative measure to deepen the reform of the approval system of engi-neering construction projects and the comprehensive survey method of multi-surveying projects,while the traditional single-point survey method is difficult to meet the needs of fast and efficient operation.Uav tilt photogrammetry technology can obtain a wide range of tilt image data in a single flight by carrying tilt camera equipment,and through image processing and 3D model recon-struction,it becomes an auxiliary operation means in"multi-survey in one"surveying and mapping.However,the conventional multi-lens tilt photogrammetry has high economic cost and is not applicable.Therefore,this paper aims to explore the applica-tion of single-lens UAV tilt photogrammetry in the combination of multiple measurements,hoping to provide a new solution for data acquisition and processing in this field.
Taking Huangyuan Bridge in Yiwu City as an example,this paper analyzes the disease of large cable tension devia-tion of rigid suspender of concrete-filled steel tubular tied arch bridge.Putting forward the basic principles of rigid suspender replacement.Providing the construction and monitoring scheme.Construction monitoring is based on the principle of dual con-trol of elevation and stress.The construction process and monitoring results show that before and after the replacement of the rigid suspender of the Huangyuan Bridge,the elevation of the rigid suspender bridge deck,the elevation of the arch rib,the stress of the arch rib,and the cable tension of the suspender meet the design requirements,which can provide a reference for the bridge maintenance and reinforcement project of the same type.
This article mainly discusses the manufacturing process of the clustered multi anchor head anchoring system.Based on the manufacturing of the anchoring system of the Yangsigang Yangtze River Bridge,the key technologies and process control points involved in the manufacturing process are analyzed,and corresponding optimization measures are proposed for the pro-cessing of refined bolt holes.Through research on this manufacturing process,the aim is to improve the reliability and stability of the clustered multi anchor head anchoring system,reduce production costs,and provide effective technical support for engi-neering practice.
By analyzing the necessity of digital transformation in the planning industry,formulating a digital transformation plan for planning,and constructing a complete big data service system.On one hand,various comprehensive urban and rural data is collected,integrated,analyzed,and presented to form a big data foundation.On the other hand,leveraging the advantages of platform systems,comprehensive,accurate,and real-time information support is provided for planning formulation and deci-sion-making,laying a solid foundation for intelligent planning.
The underground buildings need to take some certain anti-floating measures to ensure the safety,according to the en-gineering requirements to design the appropriate anti-pulling pile foundation is of great significance.In this paper,40 groups of uplift pile test data were collected from relevant literatures,and the correlation between different influencing factors was ana-lyzed.The main influencing factors were taken as input variables and the ultimate uplift bearing capacity of the expanded bot-tom pile was taken as output variables.Particle swarm optimization(PSO)algorithm is used to optimize the determination of the number and the maximum depth of decision trees in random forest(RF)method,and on this basis,a prediction model of ultimate uplift bearing capacity of expanded bottom pile is established.The results show that the coefficient of determination(R2)of PSO-RF model is 0.976,and the prediction performance of PSO-RF model is better than that of RF model(R2 = 0.954)and GMDH model(R2 =0.88).PSO-RF model can accurately predict the ultimate uplift bearing capacity of expanded bottom pile,and has good applicability in actual pile foundation engineering.
With the advent of social risk,much attention is being paid to the construction of resilient cities,where social resili-ence acts as a bridge between the various parts of society.It enables cities to balance their own structure and sustainable devel-opment in a stable and effective manner in the face of external uncertainty and risk.This paper takes the example of the Duohu-li Neighbourhood Centre in Jinhua City and reviews and constructs a resilience model for the neighbourhood centre based on the concept of social resilience.It constitutes an integrated functional unit and a resilient spatial structure with a safety-ecology-service-wisdom model in one.The theory and research provide a new model and a new planning method for the refinement of the city and the diversification of the neighbourhood centre model.
Steel structures have high strength,light weight,and uniform materials,making them widely used in engineering.However,corrosion of steel structures often leads to serious safety accidents and huge economic losses,so the corrosion problem of steel structures cannot be ignored.This study used a neutral salt spray accelerated corrosion test to simulate the long-term corrosion behavior of steel in marine atmospheric environment by exposing the specimens to a high concentration of chloride i-ons.The corrosion morphology of Q355NH and Q355 steel,as well as the mechanical properties after corrosion,were studied and analyzed.Thus,it was found that there is a power function quantitative relationship between the uniform corrosion thick-ness,corrosion pit depth,and mass loss rate of Q355NH steel and Q355 steel.In the early stages of corrosion,compared to Q355 steel,Q355NH steel has a higher corrosion rate,but under long-term corrosion,Q355NH steel has better corrosion re-sistance.
According to the problem that the residents of the six-floor masonry-structured residential building have the evident vibration sense which is caused by the students'morning running at the school located in the south of the building,the paper undertakes the comprehensive observation and the vibration detection for the building by using the vibration pickup on the spot,has the comparative analysis of the vibration affecting features caused by the school students'running on the playground be-tween classes according to the test results,and adopts reasonable and effective engineering measures accordingly to attain the better practical effect and provide some reference for similar project problems.
This paper compares engineering examples with different values of pile stiffness,attempting to study the impact of different values of pile stiffness on the stress of pile foundation.The analysis and comparison results show that different values of pile stiffness will affect the analysis results of pile force and bottom plate force.In extreme cases,it may lead to local pile failure,leading to a domino effect of overall anti floating failure.The pile stiffness also has a certain impact on the internal force results of the bottom plate,and incorrect values may cause distortion in the calculation results of the internal force of the plate,and even lead to plate failure.
This article takes a single tower double cable plane hybrid beam cable-stayed bridge as the engineering background,and combines finite element numerical simulation to analyze the cable force during the construction stage of the cable-stayed bridge;the results show that the cable force calculated using the difference method can meet the construction requirements after ten iterations;there is a coupling relationship between the cable forces of the stay cables,and the closer the distance to the changing cable force,the greater the impact on the stay cables;before the secondary tensioning,the steel beams have been fully spliced,resulting in a smaller impact of different construction methods on the secondary tensioning force of the cables,in-dicating that the internal force changes of the steel beams are more sensitive to the cable force.
The PBA construction method is mostly used in projects with large section of station structure and high requirements for settlement control.For the close underpass project,the PBA construction method will produce the group hole effect in the excavation stage of the pilot tunnel,which is not conducive to the safety of the existing station.Based on the project of Ping-guoyuan Station of Beijing Metro Line 6,this paper puts forward the advanced grouting reinforcement scheme suitable for the close underpass project,and optimizes the grouting range.It is concluded that it is more appropriate to select 1.5 m range for advanced grouting in this project;advanced grouting can reduce the group hole effect caused by pilot tunnel excavation.
In the classroom teaching of mechanics of materals,when there are complex loads acts on the beam,especially when the distributed load is expressed in a nonlinear form,the integral operation becomes tedious,with a large amount of work in the integral calculation and the intefral constant determination.Barycentric Lagrange interpolation collocation method has excellent numerical stability and high accuracy.For the beam bending problem,this method was used in this paper to get the differentia-tion Matrix of unknown function.So the control equation of beams can be expressed as linear systems by the collocation meth-od.According to those formulas,the deflection values of discrete points could be got.The principle of this method is simple and easy to be programmed.The accuracy and the numerical stability are very excellent.
This article adopts a combination of static load test and stress-strain detection method to conduct in-depth research on the working condition of prestressed concrete pipe piles.The main content is to study and analyze the load settlement curve,pile side friction resistance characteristics,and the relationship between pile side resistance and pile end resistance of the test pile.The variation law of the end resistance and side resistance of the static pressure pile is obtained,as well as the construc-tion control parameters and quality control points of the static pressure prestressed concrete pipe pile.
China's oil and gas pipelines are faced with a series of loess disasters when they pass through collapsibility loess ar-eas,and the most extensive and serious disaster is the flood disaster of loess.The key to the treatment of flood disaster is to un-derstand the influence of different landforms on flood damage and the different destruction mechanisms of flood damage.There-fore,through analyzing the destruction mechanisms of typical cases of flood damage on slope,river channel and terrace in col-lapsibility loess area,the prevention and control problems in collapsibility loess area are pointed out and the corresponding pre-vention and control countermeasures are put forward.
