Dynamic response of high-speed railway vehicle and welded turnout on large-span bridges based on rigid-flexible coupling system

Welded Turnout on Large-span Bridge(WTLB)is a complex multi-layer heterogeneous system and can significantly influence the service performance of High-Speed Railway(HSR).Understanding the coupling dynamic response of the vehicle and WTLB is essential.Previous research did not consider the dynamic behavior of foundations,leading to an underestimation of the vehicle-turnout-foundation coupling dynamic response,particularly when turnouts were laid on large-span bridges.This study proposes a novel modeling method that includes the foundations,to overcome the previous shortcomings by applying a rigid-flexible coupling system.In this approach,the vehicle was modeled as a rigid body sub-model in a Multi-Body Software(MBS),while WTLB was modeled as a flexible bodies sub-model using Finite Element(FE)software.The modal information from the FE model was imported into the MBS software.The two sub-models were coupled by the wheel-rail contact in the MBS environment and then the Vehicle-turnout-bridge Rigid-flexible Coupling Dynamic(VRCD)calculation model was established and it was discovered that the calculation results showed good agreement with the field test data.Through the VRCD model,the safety of the structure,the stability of the vehicle and the comfort of passengers were investigated,as well as several important infrastructure factors.The results demonstrate that this novel method provides accurate calculations and highlights the complex and significant interactions in the vehicle-turnout-bridge system.

大型体育场馆免低开放政策绩效研究

采用投入产出模型(DEA)分析扩大内需战略下大型体育场馆免低开放政策绩效,包括财政补助资金、场地资源的投入产出效率等;其次,以史密斯政策(Smith)执行理论为基础,围绕政策本身、执行机构、目标群体、政策环境等分析场馆免低开放政策绩效的制约因素;最后,提出场馆免低开放政策优化路径:完善场馆免低开放补贴指标体系;探索发放体育场馆健身券;优化绩效考核指标体系;加强场馆免低开放绩效评价,加快信息化建设步伐等等。

某体育场钢罩棚结构设计及施工分析

七里河体育场钢罩棚采用大悬挑钢桁架结构体系,最大悬挑长度为36.4m。经过初步设计选型及截面优化,主体结构一阶自振周期控制在0.6s左右,整体刚度较好。基于稳定性和抗倒塌分析,表明结构稳定性及极限承载力均较高,具有良好的抗倒塌能力。体育场施工过程中采取逐榀拼装、吊装,分区分步整体卸载施工方法,并对关键杆件应力、位移进行数值模拟和现场监测。结果表明,数值模拟结果与监测结果吻合较好,有效保证了施工进度和工程质量。后续对施工完成态的钢罩棚结构进行长期健康监测,监测结果表明,结构应力和变形状态均较稳定,温度变化引起的响应变化幅值均在合理范围内,满足设计要求。

Plastic zone distribution laws and its types of surrounding rock in large-span roadway

In order to study the distribution laws and types of plastic zone of surrounding rock in large-span roadway, we analyzed the distribution laws with different spans and lateral pressures using FLAC3D numerical calcu- lation software. Based on the roadway support difficulty and distribution laws of the plastic zone of sur- rounding rock, we defined the large-span roadway and classified the types of large-span rectangular roadways. As a result, the distribution laws of the plastic zone on surrounding rock in a rectangular roadway with different spans and lateral pressures were obtained. The results show that the area of the plastic zone on surrounding rock increased with the increase of the spans and lateral pressures, and the plastic zone was symmetrical to the center line of roadway. At λ=0.5, 1.0, 1.5, and 2.0, the plastic zone presented ＂addle- shape＂ distribution, ＂ellipse＂ distribution, ＂thin and high＂ distribution and ＂inverse trapezium＂ distribu- tion, respectively. In addition, we classified the roadways into four types according to the different lateral pressures and spans, including small-span, moderate-span, large-span and extreme-large-span roadways.

Development of a new type of foam concrete and its application on stability analysis of large-span soft rock tunnel

The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and low ductility was introduced.And it was made as filling material of reserved deformation layer between the first lining and the second lining used in large-span soft rock tunnel.The effect of the new type of foam concrete was simulated as filling material of reserved deformation layer using numerical simulation.Through the comparison with the common large-span soft rock tunnel,the vault settlement and surrounding convergence are reduced by about 61% and 45%,respectively,after creep of 100 a.And in the second lining,the plastic zone reduces apparently and the maximum equivalent plastic strain decreases relatively.So,it can be found that the application of the new type of foam concrete as the filling material of reserved deformation layer can relieve the excessive force in second lining induced by rock creep,reduce its deformation and improve the stability of tunnel.

In Situ Experiments on Supporting Load Effect of Large-span Deep Tunnels in Hard Rock

A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining structure.Based on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel structures.Numerical simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.

Seismic response of large-span spatial structures under multi-support and multidimensional excitations including rotational components

To achieve rational and precise seismic response predictions of large span spatial structures(LSSSs),the inherent non-uniformity and multidimensionality characteristics of earthquake ground motions should be properly taken into consideration.However,due to the limitations of available earthquake stations to record seismic rotational components,the effects of rocking and torsional earthquake components are commonly neglected in the seismic analyses of LSSSs.In this study,a newly developed method to extract the rocking and torsion components at any point along the area of a deployed dense array from the translational earthquake recordings is applied to obtain the rotational seismic inputs for a LSSS.The numerical model of an actual LSSS,the Dalian International Conference Center(DICC),is developed to study the influences of multi-support and multidimensional excitations on the seismic responses of LSSSs.The numerical results reveal that the non-uniformity and multidimensionality of ground motion input can considerably affect the dynamic response of the DICC.The specific degree of influence on the overall and local structural displacements,deformations and forces are comprehensively investigated and discussed.

Practical Applications of the Large-Eddy Simulation Technique for Wind Environment Assessment around New National Stadium, Japan (Tokyo Olympic Stadium)

In this study, we developed a new computational fluid dynamics (CFD) model called Airflow Analyst that deepens the affinity between CFD and geographic information system (GIS). First, a precise simulation of the surface-mounted cube was conducted. Validation testing based on the obtained data confirmed the predictive accuracy of Airflow Analyst. Second, New National Stadium Japan (Tokyo Olympic Stadium) was accurately reproduced in a computer, capturing the latest detailed urban area data for the base. For the target of the constructed 3D models, simulations with a large number of grid points/cells (CFD) were conducted. These simulations reproduced the complex turbulent flow fields both inside and outside the stadium. The experiment successfully reproduced the CFD simulation using a large number of grid points/cells, where the conditions of the wind flow ventilation from the sky were similar to those of the intended stadium design.

Construction Technology of Roof Membrane for World Cup Main Stadium

Based on the installation of the roof membrane of Lusail Stadium which is the main stadium of Qatar World Cup in 2022, a series of key technical challenges in the design and construction of the roof PTFE membrane of large stadiums are studied. Based on the analysis of the roof cable net system, the study formulated the overall sequence of membrane installation, and defined the construction method of membrane lifting and unfolding. Focusing on membrane fixing techniques with the tension rings, compression rings, and horizontal cable nodes, it also optimized membrane connection methods with arch and horizontal cable, and provided waterproof construction methods. According to the findings, the construction of stadium roof membranes should follow a logical sequence. The membranes’ fixing, connection and waterproof construction will have an important impact on the final quality.

我国“南气北送”工程的创新技术体系I-STADIUMS

为了缓解我国北方冬季季节性供气紧张的状况,中国海洋石油集团有限公司已经连续3年实施并扩展“南气北送”工程。为此,对该工程所形成的独具特色、反映“深耕”南方沿海市场用气技术特征的I-STADIUMS管输技术体系进行了总结。研究结果表明:①I-STADIUMS管输技术体系包括智能化(Intelligence)、小时调峰(Peak-Shaving)、组分跟踪(Quality-Tracking)、混输调质(Calorific Value Adjusting)、优化调度(Dispatching)、完整性技术(Integrity Tech)、设施第三方开放(Unbundling)、能量计量(Energy Metering)及可靠性保障(Reliability-Safeguard)共9个子体系;②I-STADIUMS充分研究并反映了粤港澳地区燃气电厂负荷占比高、小时调峰幅度大、气质稳定性要求高、不同设施主体合同用气量分配要求差异大、贸易计量方式差异大、设施开放运行、可靠性要求高等客观技术问题;③基于“资源调配优化”“管网流向优化”两项应用需求,I-STADIUMS良好地指导和优化了“产能释放”“解瓶颈”“互联互通”三类工程实践;④通过整合资源、基础设施并重组技术能力,I-STADIUMS支撑“南气北送”工程在地理范围、气量规模、外输方式、商业模式上均不断扩大、提升和创新。结论认为,该管输技术体系为因地制宜地完善我国天然气产供储销体系做出了重要贡献。

Characteristics of wind pressure pulse on large-span flat roofs

The wind pressure pulse events, among the most important characteristics of wind pressure fluctuations on large-span flat roofs, were investigated by wind tunnel tests in this paper. Incorporating the formation mechanism of wind pressure pulse events, the peak over threshold method was employed to study properties of this kind of events. The event duration time, the energy contribution, the number of the pulse events, and the distribution of average peak pressure were calculated. Probability density functions of some typical samples in separation region were also given. Results show that the non-Gaussian roof pressure is strong in the flow separation region owing to the wind pressure pulse events. Evaluations of the extreme peak pressures, which can be determined by the peak over threshold method effectively, are important to the design of building cladding.

The research on operation and management mode of domestic public stadium and Sustainable Development

Public stadiums is the hardware foundation for the development of sports enterprise, the operating status and the degree of perfection of public stadiums in a country or a region, not only reflects the level of development of sports of the countries in the region, but also it is an important symbol of modernization. However, the operation and management problems of public sports venues, are still worldwide problem, and stadiums in China face the same problem.

Stadiums’ Status Quo

IT is Saturday afternodn and a motorcade snakes its way along the Chinese-built Thika Super Highway to Moi International Sports Center, Kasarani in Nalrobi, Kenya. But the 100-plus guests and family are not headed to the stadium to watch sports. They are on their way to celebrate the wedding of Brian Jones and Annet Wanjiru.

Research on Construction Control Technology of Large-Span and Small Clear Distance Underpass High-Voltage Line Tunnel

Hanping tunnel is a control project of national highway 310 Dahejia to Qingshui highway project.It needs to cross a 330kV high-voltage transmission line under the condition of small clear distance,which requires high construction requirements.In view of the difficulties such as shallow buried depth of tunnel and small clear distance between tunnel and tower of high-voltage line,multiple excavation blasting method is adopted,and smooth blasting,charge quantity control and damping hole setting are comprehensively used to reduce the impact on the tower and structure of high-voltage line.In order to ensure the smooth progress of the project,the large-scale finite element analysis software is used to simulate the whole excavation project.The influence of the full-section method and the middle partition wall method(CD method)on the surrounding rock and the high-voltage electric tower is compared.It is found that the CD method can effectively control the displacement of the surrounding rock and the tower on it and the uneven settlement.

Distribution characteristics and the evolution law of excavation damage zone in the large-span transition section of high-speed railway tunnel based on microseismic monitoring

Purpose–The microseismic monitoring technique has great advantages on identifying the location,extent and the mechanism of damage process occurring in rock mass.This study aims to analyze distribution characteristics and the evolution law of excavation damage zone of surrounding rock based on microseismic monitoring data.Design/methodology/approach–In situ test using microseismic monitoring technique is carried out in the large-span transition tunnel of Badaling Great Wall Station of Beijing-Zhangjiakou high-speed railway.An intelligent microseismic monitoring system is built with symmetry monitoring point layout both on the mountain surface and inside the tunnel to achieve three-dimensional and all-round monitoring results.Findings–Microseismic events can be divided into high density area,medium density area and low density area according to the density distribution of microseismic events.The positions where the cumulative distribution frequencies of microseismic events are 60 and 80%are identified as the boundaries between high and medium density areas and between medium and low density areas,respectively.The high density area of microseismic events is regarded as the high excavation damage zone of surrounding rock,which is affected by the grade of surrounding rock and the span of tunnel.The prediction formulas for the depth of high excavation damage zone of surrounding rock at different tunnel positions are given considering these two parameters.The scale of the average moment magnitude parameters of microseismic events is adopted to describe the damage degree of surrounding rock.The strong positive correlation and multistage characteristics between the depth of excavation damage zone and deformation of surrounding rock are revealed.Based on the depth of high excavation damage zone of surrounding rock,the prestressed anchor cable(rod)is designed,and the safety of anchor cable(rod)design parameters is verified by the deformation results of surrounding rock.Originality/value–The research provides a new method to predict the surrounding rock damage zone of large-span tunnel and also provides a reference basis for design parameters of prestressed anchor cable(rod).

杭州运河亚运公园体育馆智能化系统工程的应用与实践(一)

杭州运河亚运公园体育馆是建筑艺术和科学技术完美的结晶,场馆流线流面卵石造型,光顺润滑、自然流畅。场馆设计采用了数字技术、绿色建筑技术与智能化技术取得了良好效果。实现了场馆建筑功能空间与体育工艺空间、建筑智能化系统与体育工艺智能化系统、建筑绿色生态与体育智慧生态完美结合。

老年群体的智慧体育场馆消费体验研究:模型构建、影响机制与适老化对策

智慧体育场馆高效的资源使用效率和丰富的服务功能,是应对老龄人口激增与体育需求高涨的有效手段,但针对老年群体特有的体育消费需求与体验障碍尚未获得充分关注和系统性研究。研究对30名老年人进行了半结构式访谈,通过程序化扎根理论提炼出行动体验、数字体验、感官体验和物质体验4个主范畴,并通过构建智慧体育场馆消费体验作用机制模型,揭示了微观、中观和宏观系统在塑造老年人消费体验中的作用。研究发现:数字体验是提升消费体验的重要阻滞;运动行为相关的行动体验最受关注;感官体验与其他范畴联系最为密切;物质体验表征的成本和价值感知是影响总体消费体验的重要因素。研究从建设标准、社会资源、服务环境、服务质量等方面对4个主范畴提出对策建议,以期助力智慧体育场馆的适老化改造,提升老年群体的消费体验。

基于KPCA⁃XGBoost机器学习的大跨体育场风荷载预测

大跨空间结构风荷载的取值是该类结构抗风设计关注重点,通常借助风洞试验或数值风洞确定,但其费用高周期长等特点限制其广泛应用.机器学习方法近年受到关注,逐渐应用于结构的风荷载预测并取得了不错的效果.利用核主成分分析(Kernel Principal Component Analysis,KPCA)对数据进行降维处理,借助可以集成学习的XGBoost机器学习模型,采用十折交叉验证对超参数进行选择,编写了基于机器学习的大跨空间结构风荷载预测程序.通过对多个已有工程项目风洞试验结果的学习训练和预测结果比对,证明该方法具有处理数据能力较强、预测效率较高及泛化能力较强等特点.随机选取未参与模型训练的风向角下数据进行模型准确性验证,结果表明模型的R2值均达到0.9左右,预测值与试验值较为接近,体型系数在迎风区的预测精度略低于背风区,而极值风压则在背风区的预测精度好于迎风区.

基于改进遗传算法的大型体育场馆传感器优化布置研究

为高效、准确地对大型体育场馆结构进行健康监测,根据其结构特点,提出了一种基于多种群非支配重组遗传算法(MP-RGA)的传感器优化布置方法。引入二重编码解决离散优化问题,通过多种群策略提高算法的搜索能力,通过非支配重组解决以往遗传算法优化后期的多样性丧失问题,最后采用自适应化交叉、变异策略改善算法前期的收敛速度和后期的寻优能力。以西安国际足球中心屋盖为例,通过数值算例验证不同传感器布置数量下利用该算法确定传感器布置方案时的有效性。结果表明:与量子遗传算法(QGA)和粒子群算法(PSO)相比,多种群非支配重组遗传算法收敛速度更快,以模态置信度准则为目标的优化效果分别提升了41.88%和91.27%;依据所提算法优化得到的传感器布置方案实际应用效果良好,表明该算法适用于大型体育场馆的传感器优化布置问题。

新世纪以来世界杯足球场建设与赛后利用经验研究

对新世纪以来世界杯球场建设与赛后利用的经验与不足进行深入分析,可为我国足球场建设与赛后利用提供借鉴。研究发现,日本、德国球场赛后利用较好,南非、巴西、俄罗斯球场赛后利用不佳,但其在建设与赛后利用方面亦有特色。世界杯球场的建设与赛后利用经验总结为:多元筹措建设资金,缓解财政负担;实施可持续发展战略,打造绿色球场;改造利用现有球场,降低建设成本;赛后削减球场容量,降低运维成本;多元复合利用球场,丰富运营内容;引入职业体育俱乐部,助推职业体育发展;引进专业管理机构,提高运营能力;成为城市更新载体,提高城市服务能力。