港珠澳大桥拱北隧道解冻,珠海连接线将全线完工

<正>2017年10月29日,利用冻结技术打造的拱北隧道完成了全部解冻工作,港珠澳大桥珠海连接线即将全线完工。拱北隧道工程是港珠澳大桥珠海连接线的核心控制性工程,也是港珠澳大桥主体工程与珠海连接的唯一通道。隧道全长2 741 m,采用双向6车道设计,由海域人工岛明挖段、口岸暗挖段以及陆域明挖段3种不同结构的隧道连接而成。在拱北隧道施工过程初期,为达到施工基础条件,工程人员利用36根直径1.62 m,长255 m,具有冷冻功能的特殊钢管先行     

港珠澳大桥珠海连接线工程拱北隧道设计

正在设计建设中的港珠澳大桥珠海连接线工程拱北隧道总长2741m,采用双层明挖+局部双层暗挖双向六车道的隧道形式,隧道施工采用了先岛后隧明挖法和大断面、长距离、多管节、曲线管幕顶进方法.隧道具有断面大、埋深小、地层软弱、地下水丰富、周边环境敏感等特点,是目前我国已建及在建的水下公路隧道中环境条件最复杂、施工难度最大、综合技术含量最高的隧道工程之一.     

港珠澳大桥珠海连接线拱北隧道深基坑施工技术

港珠澳大桥珠海连接线拱北隧道明挖段总长2 455m,分海域明挖段和陆域明挖段,海域明挖段采用先填筑人工岛后隧道开挖,陆域采用明挖顺作。分别从围护结构、开挖、地基加固、主体结构施工等方面对拱北隧道深基坑施工技术进行了探讨。     

大断面城际铁路隧道近接桩基施工方案研究

针对某城际铁路隧道近距侧穿立交桥桩基设计和施工方案,采用有限差分法对隧道明挖和暗挖两种方案施工对桩基内力影响进行了三维数值分析,计算获得了各隧道施工方案下各立交桥桩基最大轴力、弯矩和最小安全数,同时通过对比分析可知,暗挖施工方案优于明挖施工方案,其中轴力最大增加约24.2%,弯矩最大增加约282.3%,安全系数减小74.5%,推荐使用暗挖施工方案进行施工作业。研究成果为既有立交桥的正常运营以及隧道施工的顺利进行提供了保证,并可为相似工程提供参考。     

PBA暗挖车站与盾构隧道重叠施工的影响分析

以北京地铁某线明暗挖结合的地下车站为例,对3种不同的施工工况,采用Ansys程序模拟计算分析了盾构隧道及车站施工对地面沉降的影响及车站与区间隧道的相互影响。计算分析结果表明,采用工况1方案,即盾构在暗挖段上导洞施工完毕,暗挖段顶梁、中柱没有施工的情况下穿越,盾构隧道与车站暗挖结构相互影响较小,施工难度及风险在3种施工工况中最小。     

港珠澳大桥珠海连接线拱北隧道注浆综合施工技术

港珠澳大桥珠海连接线拱北隧道工程位于珠江口临海软土地区,下穿国内第一大陆路口岸拱北口岸,采用"曲线管幕+水平冻结+五台阶十四部"工法施工。注浆加固和止水是软土地质常见的施工辅助措施,结合拱北隧道暗挖段,详细介绍管幕安装、人工冷冻、大断面开挖及冻结圈解冻等不同施工阶段的辅助注浆施工技术,并针对各种注浆技术的作用、特点、工艺、效果等进行重点分析。     

城市浅埋隧道设计与施工方法研究

城市发展过程中,交通与环境的矛盾日益突出,为了保全地面结构物,采用隧道方寨的也越来越多。城市隧道最显著的特征是浅埋、地面结构物复杂、围岩差。文中结合厦门市机场路一期工程梧村山隧道的莲前西路下穿道这一具体工程,在分析现有城市浅埋隧道施工方案的基础上,通过优化施工步骤和支护参数,结合有限元分析计算,验证展线明挖方案和管幕暗挖两种方案都是合理可行的,考虑到投资和施工风险,最终决定采用展线明挖方案。     

城市复杂环境地铁暗挖施工量测技术

文章针对极为复杂的广州市轨道交通11号线(环线)流花路站暗挖安全施工控制难题,在对工程地质和周边环境条件分析的基础上,结合包含4个临时竖井、1个半盖挖明挖段、4个横通道以及洞桩法施工车站主体开挖方案,确定了主要包括地表、建筑物、管线及基坑支护体系的总体监测方案。结果表明,工程施工过程测得数据均在控制标准范围内,复杂环境下的城市地铁暗挖施工安全,同时也能保证周边建筑风险可控。     

近海人工填筑砂石段地连墙成槽施工技术例析

拱北隧道海域明挖段在地下连续墙施工时,采取了振冲,砂桩,搅拌桩、旋喷桩槽壁预加固,冲抓结合穿越填石层等措施,总结出了一整套关键施工技术。     

深圳地铁3C标段桩基托换工程质量控制

一、概况（一）、工程概况深圳地铁一期工程3C标段由明挖区间隧道和暗挖区间隧道两部分组成，其中暗挖区间隧道须从百货广场裙楼桩基础群中和华中国际酒店桩基础地基中穿越。为减少因隧道施工对建筑物地基基础的影响范围，该段区间隧道的结构型式采用单洞双层重叠隧道，矿山法施工。在隧道施工之前，需采用可靠的技术方案对隧道施工影响范围内建筑物的桩基础进行托换，使其上部结构荷载通过托换结构转换到隧道施工范围以外的新桩基础上，以确保建筑物的正常安全使用。①华中酒店桩基托换华中酒店主楼12层，裙楼3层，无地下室，须托换门廊二…     

Multi-attribute group decision making model under the condition of uncertain information

Owing to the increasing complexity in the construction management, integrating experts' knowledge and experiences to make appropriate decisions is a commonly used method. TOPSIS (technique for order performance by similarity to ideal solution) is a practical and useful technique in dealing with multi-attribute decision making problems, and has been widely employed in the construction management and other fields. The modification and extension of TOPSIS to a group decision environment is investigated in this study. In the proposed group decision making model, we both adopt the Minkowski distance function to solve the over-weighted problem in the original TOPSIS technique, the grey number operations to deal with the problem of uncertain information, and the aggregation approach to integrate experts' evaluations. Finally, an illustrative example of subcontractor selection is used to demonstrate the feasibility and practicability of the proposed model.     

基于FG-MCGDM的水利工程施工进度方案优化

针对水利工程施工进度的多准则群决策问题,提出了一种新的模糊灰色多准则决策模型。该模型基于模糊集理论、灰色关联分析和折衷解的理论方法,将各决策属性和决策者权重的语言变量转化为梯形模糊数;采用改进的 GRA-VIKOR方法对模糊信息群体决策问题进行求解,并对各决策者的群体效益值和个体遗憾值进行聚合;通过折衷解对施工进度方案进行排序,获得最优方案。该模型有效地避免了信息的扭曲和丢失,确保了决策信息的完备性。通过在某水利工程施工进度方案优选的案例分析与计算,证明了该模型的有效性和实用性。     

富水软土长距离非锁口曲线管幕施工风险研究

非锁口曲线管幕工法是为适应复杂地下环境与工程障碍物而发展的隧道非开挖新技术,其施工过程的风险控制是十分值得重视的研究课题,特别是富水软土隧道。本文结合港珠澳大桥拱北隧道暗挖工程,重点研究富水软土长距离非锁口曲线管幕工程施工的风险评估问题。基于富水软土中长距离非锁口曲线管幕施工进行风险分析,得到风险因素对总评指标的权重,再采用专家调查法对单因素进行评价,得到模糊关系矩阵,然后进行合成计算得到综合评判集,建立基于层次分析法的风险模糊评估方法和标准。最后运用该方法对港珠澳大桥拱北隧道管幕工程的施工风险进行分析评估,绘制了风险因素分布直方图,计算得到了综合风险等级,提出了风险控制建议。     

A decision support system for super tall building development

Super tall building projects commonly inherit a slow and lengthy decision making process due to financial uncertainties, in spite of large investments. However, current decision‐making practices depend upon detailed cost estimating and scheduling during the design development phase and not rough cost estimating and scheduling during the schematic design phase. Discrepancies between a project budget and program with estimated construction cost and construction period often result in architect and consultants having to perform costly re‐design work. To mitigate these issues, this study proposes a decision support system (DSS) model. An interim design development phase is introduced between the schematic design phase and the design development phase. Design alternative generation, database, cost and schedule estimation modules are developed. The design alternative generation module provides design alternatives that change proportionately in response to increases or decreases in the number of building stories. The database module is established for cost and schedule estimation modules. The cost and schedule estimation modules produce construction costs and construction period for design alternatives. Finally, the proposed DSS is validated through the case study of an ongoing real super tall building. Ultimately, the new DSS can assist project control groups in performing efficient and financially beneficial decision making in terms of construction cost and construction period. This research provides a fundamental step towards the development of the DSS for super tall building projects. Copyright © 2012 John Wiley & Sons, Ltd.     

A multi-dimensional approach to the assessment of tunnel excavation methods

Selection of tunnel excavation method in rock calls for an exact assessment of engineering geology as well as geotechnical conditions of the tunnel strike. Moreover, uncertainties related to properties of engineering geology of rock often trigger complexity. In order to select the best possible excavation technique, one needs to take into account numerous operational, economic, environmental factors, and so forth. Using a hybrid methodology, including multiple attributes decision-making techniques and fuzzy set theory, the present study aims to evaluate the excavation methods of tunnels. The proposed approach is based on fuzzy-AHP and TOPSIS methods where the fuzzy-AHP determines weights of the criteria by decision makers in uncertain environment and TOPSIS concludes rankings of the excavation methods. Finally, a case study of Ghomroud project in Iran is presented to demonstrate the result of the proposed methodology.     

单层网壳结构的模糊决策分析

本文提出了单层网壳结构的模糊决策方法 ,其中决策模型的目标函数中不仅考虑了单层网壳结构的杆件费用和节点费用 ,而且还考虑了结构的维护费用以及遇到自然灾害时损失的期望值 ,另外在约束条件中考虑了强度、刚度、稳定等因素中存在的模糊信息 ,从而构成了单层网壳结构的模糊决策问题。在其模糊决策问题的求解过程中 ,分两个阶段进行求解。在第一阶段 ,以结构造价为目标函数 ,求解其模糊最小设计 ;而在第二阶段是在第一阶段中求出的模糊最小设计的基础上 ,进一步考虑结构的维护费用和损失期望值 ,求出单层网壳结构的最终模糊优化解。     

基于范例的基坑支护方案选择决策支持系统

指出基坑支护方案的选择直接关系到工程造价、施工进度以及基坑周边环境安全,针对基坑处理决策中的基坑支护方案选择问题,提出一种基于范例的基坑支护方案选择系统,用以对基坑支护方案选择提供有效的决策支持。     

谈建设项目决策分析与评价

阐述了建设项目决策分析与评价的重要性 ,介绍了其基本工作要求、程序和主要内容 ,指出建设项目决策分析与评价是企业取得经济效益的重要手段     

不同工况下扩建工程边坡开挖方案的有限元分析

在道路扩建工程中,新、旧路堤结合部易产生较大的差异变形,施工中常采用开挖台阶的方式来增强新、旧路堤间的联结。结合实际工况,对路堤间差异变形进行计算分析,结果表明:差异变形与开挖方案密切相关,旧路边坡开挖量越大,差异变形也越大。当路堤填高不超过5m时,小台阶开挖方案和大台阶开挖方案产生的差异变形较为接近,为方便施工可选用大台阶开挖方案。但当填高大于5m时,大台阶开挖方案将产生较大的差异变形,导致结合部的破坏,建议选用小台阶方案。     

Decision‐making in a model‐based design process

Decisions early in the design process have a big impact on the life cycle performance of a building. The outcome of a construction project can be improved if different design options can rapidly be analysed to assist the client and design team in making informed decisions in the design process. A model‐based design approach can facilitate the decision‐making process if the design alternatives' performances can be evaluated and compared. A decision‐making framework using a performance‐based design process in the early design phase is proposed. It is developed to support decision‐makers to take informed decisions regarding the life cycle performance of a building. A scenario is developed in order to demonstrate the proposed framework of evaluating the different design alternatives' energy performance. The framework is applicable to decision‐making in a structured design process, where design alternatives consisting of both objective and subjective evaluation criteria can be evaluated.