HY-1C Coastal Zone Imager observations of the suspended sediment content distribution details in the sea area near Hong Kong-Zhuhai-Macao Bridge in China

The impacts of the Hong Kong-Zhuhai-Macao Bridge(HKZMB)on suspended sediment content(SSC)were analysed in the Zhujiang River Estuary based on data from HY-1C,which was launched in September 2018 in China,carrying Coastal Zone Imager(CZI)and Chinese Ocean Color and Temperature Scanner on it.A new SSC inversion model was established based on the relationship between in-situ SSC and the remote sensing reflectance in red and near-infrared bands of CZI image.HY-1C satellite data obtained from October to December 2019 were applied to retrieve SSC in the Zhujiang River Estuary.The results show that SSC around the HKZMB is ranging from 20 mg/L to 95 mg/L.SSC change obviously on two sides of the bridge.During flooding and ebbing period,SSC increases obviously downstream of the bridge.SSC difference between upstream and downstream is ranging from 5 mg/L to 20 mg/L.Currents flowing across the HKZMB,the change trend of SSC in most places upstream and downstream is almost the same that SSC downstream of the bridge is higher than SSC upstream.The tidal currents interact with bridge piers,inducing vortexes downstream,leading the sediment to re-suspend downstream of the bridge piers.Other factors,including seafloor topography and wind,can also contribute to the distribution of SSC in the Zhujiang River Estuary.

Pavement structure and materials design for sea-crossing bridges and tunnel:Case study of the Hong Kong-Zhuhai-Macao Bridge

With the continuous development of bridge and tunnel construction technologies,large-scale sea-crossing bridges and tunnels have gradually become the preferred choice for regional traffic.The construction technology of Hong Kong-Zhuhai-Macao Bridge(HZMB),one of the most representative sea-crossing passageways,is instructive for the construction of other large sea-crossing infrastructures.At present,the pavement design method of sea-crossing passageways lacks pertinence as it still refers to specifications for design of common pavement.Therefore,it is necessary to consider the bridge and tunnel pavement of HZMB as a typical example to analyze key technical problems encountered in its design,construction and operation.Novel solutions for material selection and structural design built upon the analysis of such critical problems should thus follow up.Based on comprehensive literature research,it can be found that environmental variability,tunnel closure,structural differential settlement and expansion deformation are the key technical problems faced by pavement of sea-crossing passageways.In view of the environmental variability,the steel deck-paving material and structure design of GMA-10 t SMA-13 is innovatively proposed.As for the closure of immersed tube tunnel,warm-mix flame retardant asphalt mixture is used to control pavement design through key indexes such as temperature and limit oxygen index.Regarding the deformation of immersed pipe joints,BJ200 asphalt seamless expansion joint material is introduced,which effectively satisfies the multi-directional deformation between pipe joints and ensures the smoothness of the road surface and driving comfort.For segmental joints,double-layer waterproof-coiled material is used to effectively prevent reflective cracks while ensuring the continuity of asphalt concrete pavement.Therefore,this paper provides a panel of ideas and methods for the pavement design of the same type of sea-crossing passageways.

A fuzzy model for assessing the risk exposure of procuring infrastructure mega-projects through public-private partnership： The case of Hong Kong-Zhuhai-Macao Bridge

Considering the rapid urbanization growth rate particularly in developing countries, the number of infrastructure mega-projects over the past years has risen tremendously. Essentially, because infrastructure megaprojects require huge investment funds, better management skills, well qualified and experienced international expertise and technology innovation, they are mostly preferred to be procured using the PPP method compare to the use of the traditional bid-build system. In this regard, this paper aims to develop a fuzzy evaluation model for assessing the suitability of procuring infrastructure mega-projects through PPP by considering their risk exposure. The main body of Hong Kong-Zhuhai-Macao Bridge(HZMB)is used as a case project to demonstrate the practicality of the risk evaluation model. The risk evaluation model consists of four critical risk groupings, these include,construction and land risks, commercial risks, operational risks and political risks. Using the risk evaluation equation,a risk index of 4.53 out of 5.00 is computed for the selected project if it is procured through the PPP scheme. This outcome shows that the case project is not suitable for the PPP approach because its risk exposure is very high. The model developed will enable PPP practitioners to predict the likely risk exposure of procuring infrastructure megaprojects through the PPP scheme.

Meta-synthesis management framework of a complex project： A case study of the deck pavement project of the Hong Kong-Zhuhai-Macao Bridge

Innovative technology and deep uncertainty during the design and construction process of complex projects introduce great challenges to their organization and management.The traditional methods,represented in the project management body of knowledge(PMBOK)guide,can solve systematic problems;however,they cannot solve complex problems.Based on the management practice implemented in the deck pavement project of the Hong Kong-Zhuhai-Macao Bridge(HZMB),in this work,we propose a meta-synthesis management framework for a complex project from the perspective of the science of complexity.The method deems that the complexity of the project has the characteristic of being multi-scale both in the design phase and the construction phase.These problems can be classified into different categories,each of which requires a different strategy.As a result,it is first necessary to adopt the"exploration"strategy to reduce project complexity and to transform the deep uncertainty problems into systematic problems.Then,the"exploitation"strategy should be used to apply the PMBOK and other traditional methods to achieve the design and construction goals of the project and to improve its efficiency.More specifically,in the design phase of a complex project,the"innovative integration"process is used for the exploration of the new engineering technology and knowledge;then,the"functional integration"process is employed to define the system architecture,the interface relationship,the technical index,and other functions.In the construction phase,the"adaptive integration"process is used for the construction of the engineering organization system;next,the"efficient integration"process is employed to improve the actual construction performance.The meta-synthesis management framework proposed in this work reveals the multi-scale principle of solving complex problems in the management practice of a complex project,and develops the methodology of metasynthesis.

Social responsibility in infrastructure mega-projects： A case study of ecological compensation for Sousa chinensis during the construction of the Hong Kong-Zhuhai-Macao Bridge

Ecological compensation plays an important role in implementing the social responsibility of infrastructure mega-projects. Based on the results of a field study, an in-depth interview, and archive data, this paper introduces the ecological compensation for Sousa chinensis(the Indo-Pacific humpbacked dolphin) during the construction of the Hong Kong-Zhuhai-Macao Bridge. It studies the concrete measures, decision-making processes,and organizational collaboration of the ecological compensation, using the method of a case study. The present study not only enriches our understanding of the ecological compensation practice during the construction of infrastructure mega-projects, but also extends the literature on the social responsibility of infrastructure mega-projects.This sheds light on the protection of the environment as well as biodiversity in the construction of future infrastructure mega-projects.

How does the improved DB mode degrade the complex integrity of infrastructure mega-projects？ Evidence from the Hong Kong-Zhuhai-Macao Bridge project in China

Complex integrity is one of the main characteristics of infrastructure mega-projects(IMPs). Cost,technology, risk, duration, environmental impact, and other uncertain complexities are interrelated and constitute a challenging and complex management problem. At present, there is no unified understanding of or solutions to these complex integrity problems. This study analyzes the complex integrity of the island-tunnel subproject of the Hong Kong-Zhuhai-Macao Bridge(HZMB) project and proposes an improved design-build(DB) mode in which the owner provides a preliminary design and has the right to form and manage consortium. This improved DB mode creatively degrades the special complexities that arise from multiple dimensions. On this basis, it is an efficacious way to grasp the main contradictions, integrate the effective resources, and degrade the complex integrity in multiple dimensions and at multiple levels so as to effectively deal with the complexity management of IMPs.

Coupling and evolution mechanism of infrastructure mega-projects complex ecosystem： Case study on Hong Kong-Zhuhai-Macao Bridge

Infrastructure mega-projects(IMP), which involve complex interactions and feedback, have more significant impact on economic, social, and other systems.This paper proposes a concept—the IMP complex ecosystem—to analyze IMP from a broad perspective of organic links across engineering, social, economic, and resource environments. Moreover, this paper proposes the theoretical concept, framework, and functions for the IMP complex ecosystem based on complex ecosystem theory.First, the coupling process between IMP complex ecosystem subsystems is analyzed through material flows, energy flows, information flows, and value streams.Second, a logistic model of the IMP complex ecosystem is proposed by analyzing the evolution conditions and motivations. Third, the evolution pattern of the IMP complex ecosystem is determined. Fourth, the positive evolution strategy of the IMP complex ecosystem based on dissipative structure theory and the influencing factors of the evolutionary process is introduced. Finally, the Hong Kong-Zhuhai-Macao Bridge and Sousa chinensis are used as the case study. This paper also analyzes the coupling structure on the complex ecosystem of the Hong KongZhuhai-Macao Bridge and investigates the coupling and evolution mechanism application of the IMP complex ecosystem on Sousa chinensis protection for the Hong Kong-Zhuhai-Macao Bridge project.

港珠澳协同背景下跨境电商物流国际竞争力提升路径研究——基于模糊层次分析法

跨境电子商务对比传统贸易方式有利于优化资源配置以及推动我国经济增长方式实现全面转变。港珠澳协同背景下,跨境电子商务在对外贸易中的比重连年保持攀升态势,是非常重要的对外贸易增长点,而跨境电商又是以物流作为支撑。由此,本文围绕港珠澳协同背景下跨境电商物流国际竞争力提升路径展开深入研究具有积极意义。

基于SD模型的重大工程项目成功要素仿真研究

为实现重大工程项目的安全运行和可持续发展,运用系统动力学对重大工程项目成功要素进行仿真研究。首先,识别重大工程项目成功要素,构建其指标体系;其次,分析各成功要素间的作用关系,构建重大工程项目成功要素SD模型;最后,以港珠澳大桥为例,运用Vensim软件进行模拟仿真,并对12个常量型成功要素进行敏感性分析。结果表明:增加对认知情感、高管领导、行为关系、资源整合和组织学习的投入和管控,促进重大工程项目成功;对重大工程项目成功影响显著的要素为重大工程项目管理经验、财务冗余度、数字科技的应用和行为惯性。该研究拓展了重大工程项目成功要素研究,为促进重大工程项目成功提供理论依据。

跨海钢箱梁桥合龙过程瞬态温度效应分析

为研究外海水域跨海桥梁建造过程中瞬态温度效应,以港珠澳大桥——跨越崖13-1气田管线桥为工程背景,采用理论研究与数值仿真相结合的方法对其合龙过程中在热带强日照辐射、大气对流状态下的瞬态温度梯度及其响应进行精细化分析与预测。首先建立日照辐射与大气对流作用下主梁外表面统一热流密度偏微分方程,求解得到主梁外表面任一时刻等效综合温度;其次建立主梁截面热传导数值分析模型,求解截面瞬态温度梯度分布,并与实测温度梯度数据进行对比验证;最后计算主梁合龙过程中在瞬态温度梯度作用下的温度效应。研究结果表明:跨越崖13-1气田管线桥的瞬态温度梯度预测值与实测值一致(最大偏差小于2℃),且预测值稍大于实测值,使结构偏于安全。合龙过程中主梁温度梯度具有明显的非线性特征:在距离顶板顶面0.4m范围内,温度梯度较高,而在0.4m以外,温度梯度逐渐趋于0。主梁最佳合龙时段为合龙当天晚上21:00至第二天上午6:00,对于最佳合龙时段合龙口两端存在微小转角的问题,可采取设置临时调位千斤顶及施加临时配重的方式加以消除。

基于NK模型的重大工程决策关联复杂性分析

关联复杂性是重大工程决策过程中的重要特征,但相关研究较多在传统的项目管理框架内展开,显现出一定片面性和局限性。为此,将NK模型引入重大工程决策关联复杂性分析,通过梳理国内外相关研究,对重大工程决策关联复杂性作出定义并明确其具有的关联性、非线性、自适应性等特征内涵;从决策环境、主体和目标出发,分析重大工程决策关联复杂性并构建理论模型;以港珠澳大桥为例,提出重大工程决策关联复杂性带来的4个主要问题:决策结构、决策权力、主导决策和内外部关联性问题,并引入模块化影响矩阵、适应性游走方式、基因型搜索方式和参数K、C仿真等NK模型所特有的问题解决方法。结果表明,基于NK模型的问题解决方法能够较好地契合重大工程决策过程中各决策点自下而上彼此关联、交互影响的特征,为后续相关研究提供了模型框架和理论参考。

地震波斜入射下港珠澳大桥沉管隧道地震响应分析

斜入射地震波引起的非一致性地震动对地下管廊、沉管隧道等细长结构影响明显。在细长结构抗震中,需要考虑地震动的非一致性。针对港珠澳大桥沉管隧道,采用黏弹性人工边界的方法建立三维有限元模型,对比分析P波、SV波和SH波在不同角度斜入射下的隧道动力响应。研究结果表明:不同的入射波、不同的角度在隧道中的响应差别显著。P波、SH波作用下结构加速度随入射角的变化先增大后减小,SV波作用下结构加速度随入射角增大而减小。相较于自下而上的垂直入射,地震波斜入射下结构应力响应被明显放大且不同入射波下结构应力响应的分布特点不同,P波在隧道顶、底板的中部的应力较大,SV波作用下结构纵向非一致性表现得更明显,SH波在隧道侧墙、中隔墙与顶底板相交的角点区以及两个斜向板块应力较大。随着入射角度增大,P波、SV波应力逐渐增大,SH波应力逐渐减小。

港珠澳大桥贸易物流通道的问题与对策研究

文中对港珠澳大桥贸易物流通道的现状及问题进行分析,通过对东莞市中的“香港国际机场物流园”贸易通关模式及广港深铁路运维的经验借鉴,对应从港珠澳大桥物流基础设施的应用、三地政策及机制的衔接、信息机制及产业的协同及跨境金融方面的创新四个方面提出发展对策建议。

改革开放前后供应港澳出口商品生产基地的建设--以珠海为例

供应港澳出口商品生产基地的建设是勾连珠海经济特区设立前后历史的重要常量。中央政府的推动和地方政府的实践促成了供应港澳出口商品生产基地的建设。改革开放初期,珠海利用地利之便和政策优势,通过开发土地资源、调整农业结构、建立示范基地和兴办相关企业等方式,在推动出口商品生产基地建设的同时,促进了自身对外贸易的发展。

管幕冻结法积极冻结方案模型试验研究

港珠澳大桥珠海连接线拱北隧道工程预支护体系采用管幕法与人工冻结技术相结合的全新"管幕冻结法"施工。根据工程实际情况,首次提出了在管幕钢管内部布置"圆形主力冻结管"、"异形加强冻结管"和"升温盐水限位管"三种特殊管路构成的冻结方案。为了研究该冻结方案的有效性与可控性,进行了大型物理模型试验。文章主要介绍了模型试验概况,重点分析了开挖前积极冻结阶段冻结的试验效果。试验结果表明,积极冻结阶段冻土帷幕发展显现了预期规律,冻结效果显著;管幕间形成良好的冻土帷幕,可确保良好的止水效果。

港珠澳大桥人工岛对水沙动力环境的影响

为了评估港珠澳大桥人工岛建设对周边海区水沙动力环境的影响,针对人工岛设计及工程海区水沙特性,建立了整体潮流泥沙物理模型,系统研究了人工岛建设引起的动力地貌演变效应。试验结果表明,受岛体阻水影响,潮流在人工岛两端分别形成双向绕流,流速明显增大,并在岛桥结合部与岛隧结合部发育局部冲刷坑;人工岛背水面同时存在多个大小不一的强紊动小尺度回流,并具有不断形成、发育、发展到消亡的周期性变化过程。受人工岛自身位置、形态、尺度以及工程海区地形、水流、泥沙等因素影响,港珠澳大桥东、西两个人工岛引起的动力地貌演变效应,既在变化规律上具有较好的一致性,又在影响形式与程度上存在明显的差异性。

港珠澳大桥对伶仃洋河口潮流环境的影响

伶仃洋为弱潮河口,潮差较小,平均潮差为0.86～1.69 m,最大潮差为2.29～3.36 m.伶仃洋潮汐动力远远强于径流动力,潮流是塑造和控制滩槽格局的主要动力因素.通过伶仃洋河口潮流物理模型试验,研究港珠澳大桥建设对伶仃洋河口潮流动力环境的影响.研究结果表明:港珠澳大桥的建设对潮底动力环境影响的范围和强度表现为东部人工岛附近较强,西部桥区附近相对较小;近桥局部区域潮位及流场的变化比较明显,远离桥轴线5 000 m以外区域变化较小.

挤密砂桩加固水下软土大型原位载荷试验研究

港珠澳大桥岛隧工程水下深厚软土采用挤密砂桩进行加固,设计了一套大型原位载荷试验系统对水下挤密砂桩(sand compaction pile,SCP)复合地基的力学和变形特性进行研究,通过在水下设置高精度静力水准系统获得了良好的沉降观测结果。试验结果表明,水下挤密砂桩复合地基在同一置换率下的应力分担比与载荷水平以及时间效应密切相关;应力分担比比值随荷载级别的升高表现出先减小后增大的趋势,在同一荷载级别下比值随着时间逐步衰减,并最终趋于某一定值。对比分析了几种散体材料桩复合地基承载力理论的计算结果,表明按被动土压力法得到的复合地基承载力与载荷试验结果较为接近。对于高置换率的挤密砂桩复合地基,采用建筑地基处理技术规范提出的沉降折减系数计算得到的复合地基沉降与实测值最为接近,采用日本经验公式计算得到的沉降量偏大。研究结果对于水下挤密砂桩复合地基的设计计算和深水原位测试具有一定的参考意义。

港珠澳大桥沉管隧道基槽泥沙回淤研究总述及创新实践

港珠澳大桥海底隧道施工采用沉管工法,在E15节沉管施放中发生了基槽异常回淤,迫使沉管返航,造成了巨大的工程损失。明确异常回淤机理,实现基槽泥沙回淤的精确预报具有重大的工程意义。通过开展大量自主创新性研究工作,揭示了基槽异常回淤的原因,开发了沉管基槽多因素、复合型基槽回淤预报模型系统,实现了沉管基床上泥沙回淤的精细化预报,保障了E15~E33节沉管的顺利安放。研究成果从基础理论、模拟技术、预警预报模式等多个方面均取得了开创性突破,对我国工程建设和泥沙研究的理论具有极大的提升和促进意义。

港珠澳大桥主体混凝土结构120a使用寿命耐久性对策

跨越伶仃洋海域的港珠澳大桥提出了120 a使用寿命的建设目标,如何提高外海、高温、高湿环境下混凝土结构耐久性是工程建设面临的重大问题之一。结合港珠澳大桥工程实践,在工程建设前期和设计施工阶段,开展了针对混凝土结构耐久性的系列研究工作。在研究成果基础上,从耐久性设计、施工及后期维护等方面,提出了为确保港珠澳大桥达到120 a使用寿命所应采取的耐久性对策和措施。