隧道周围建筑物对隧道盖板周围地表沉降的影响

在隧道暗挖施工过程中,周围建筑物对地表沉降变形的影响,在一定的工程条件下,可以用随机介质模型和弹性力学的公式进行分析。文章在分析介质模型的理论基础上,对隧道暗挖工程中对地表沉降和变形的因素进行了分析,如周围建筑物,疏水引起的地表沉降及移动,开挖过程本身引起的变行和移动等。     

双线隧道不同净距下施工变形特征研究

本研究运用MIDAS-NX软件对双线隧道在不同净距条件下的施工变形进行数值模拟,探讨隧道净距对地表变形及地质响应的影响。研究结果显示,隧道净距对地表沉降槽的深度、宽度和分布具有显著影响,随着隧道净距的增大,地表沉降槽逐渐变宽、变浅。当隧道净距小于2D时,地表沉降槽呈正态分布,最大沉降值位于双线隧道的中间位置;而当隧道净距大于2D时,地表沉降槽呈“W”状,最大沉降值出现在先行线的地表中间位置。实际施工过程中,为确保地表最大沉降值满足地表位移控制标准,必须保证双线隧道有足够的间距。     

海域超软土地层大直径盾构掘进控制研究

随着我国轨道交通事业的高速发展,穿江越海盾构工程逐年增加,地层稳定性分析及控制成为研究热点。本文以粤港澳大湾区横琴杧洲穿海盾构隧道工程为工程实例,通过PLAXIS 3D建立三维有限元模型,定量分析了盾构掘进过程加固范围、地表沉降等时变特征。结合现场实测数据,明确了海域超软土地层大直径盾构掘进过程中地层的变形规律,验证了数值模拟的可靠性。研究表明：盾构隧道开挖时,地表允许最大沉降为20mm,当t>0.15D,地表沉降满足要求,加固范围取0.20D最为合理,当t=0.00D时,地表最大沉降约50mm,当t=0.20D时,地表最大沉降约8mm,相比t=0.00D最大沉降减少约84%。结合研究结果所得规律,设计了盾构隧道软土地基加固方案,取得了理想效果。研究可为类似工程提供有价值的参考。     

深埋盾构掘进环境扰动数值分析

盾构隧道在建设过程中,常会受到一些环境因素的干扰从而导致一些严重的后果。本文利用ABAQUS建立盾构隧道掘进的数值模型,对整个施工过程进行模拟,计算盾构管片拼装的局部受力与变形、以及整体纵向的拼装变形,以及地层的分层沉降等,分析了盾尾里程与横向地表沉降关系、不同施工阶段横向地表沉降规律以及盾构推进引起纵向地表沉降分析、管片变形等盾构施工扰动机理。分析结果对研究深埋盾构隧道穿越过程中隧道微扰动影响,制定施工安全技术标准,实现大深度盾构隧道安全高效施工具有一定参考价值。     

盾构下穿既有线时素桩加固体系的研究

在远期规划线下穿既有线的案例逐渐增多的背景下，既有线变形控制措施成为当下研究热点。本文提出一种素混凝土桩加固体系，以成都地铁5号线上下交叠隧道为工程实例，通过Midas GTS有限元软件建立三维模型对比分析地铁隧道在采取素混凝土桩加固体系前后施工对既有隧道结构的变形特征。结合现场数据，明确地表沉降和既有隧道沉降的影响规律，验证了数值建模方法的可靠性。研究表明：素混凝土桩辅以袖阀管注浆的组合加固后上覆既有结构的变形从沉降普遍变为隆起，且隆起值符合控制标准；既有隧道竖向位移、水平位移峰值及地表沉降在加固后分别减小100%（隆起减小67.22%）、74.07%、80.48%，加固效果显著。现场数据表明，地表沉降和既有隧道拱顶沉降在下穿过程中急剧增大，采用素桩加固体系后明显减小，对比数值模拟结果，两者吻合程度较好，地表沉降和拱顶沉降的误差分别为21.4%和33.9%。本研究可为类似工程施工提供指导。     

盾构法施工引起的地面沉降浅析

文中针对盾构施工过程中的地面沉降进行了浅析,主要分析目标为苏州地铁2号线迎尹区间国香雅苑小区,文中对盾构法施工造成地表沉降的发展过程进行了简要分析。对地铁采用盾构法施工的铁区间隧道引起地表沉降的原因、过程及规律进行了较为详细的分析,并结合地铁隧道盾构法施工工程实例,利用线性回归计算理论拟合观测点的线性方程,来预测地表沉降和指导安全高效的施工。最后将分析数据与工程实际监测测量数据进行对比,得出相应的结果并提出防止地表沉降的控制措施,以期为类似工程施工提供有益的参考和帮助。     

大跨度浅埋黄土隧道下穿高速公路的施工技术

本文以郑西客运专线阌乡隧道为例,介绍了大跨度浅埋黄土隧道下穿正在运营的高速公路时所采取的超前支护、掌子面预加固、初期支护、临时支护等关键施工技术,并对双侧壁导坑开挖过程中的拱顶沉降、洞内收敛和地表沉降等变形规律进行了归纳总结,为类似工程的设计和施工提供了可靠的实践经验。     

地铁区间隧道开挖对临近建筑结构内力及变形影响的分析研究

北京地铁i5号线安立路站与大屯路东站之间需设置竖井进行区间隧道的开挖。为了解竖井及区间隧道开挖对临近建筑结构内力及变形的影响，采用数值方法，计算分析了开挖过程中临近建筑结构内力及变形的变化情况。结果表明地下开挖对临近建筑结构梁的影响明显大于对柱的影响；地下开挖引起的地表沉降曲线近似于正态曲线；随着到开挖位置距离的增大，地表沉降值逐渐减小，当距离达到3-4倍开挖内径时，沉降量基本可以忽略。     

浅埋隧道地表开裂处理及隧道施工技术管理

本文基于新建宝鸡至兰州客运专线范家窝隧道为例,介绍了位于黄土浅埋偏压地段,土体含水量大,有垮塌及地表开裂现象的隧道施工,通过对超前支护、掌子面预加固、初期支护及临时支护等关键施工工艺技术的论述,对三台阶七步开挖法施工过程中的拱顶沉降量、洞内收敛和地表沉降等变形规律归纳总结,为以后类似工程施工提供了相关的实践经验.     

重庆丰盛场区域山体变形对隧道开挖响应特性研究

采矿时隧道开挖会对地下环境造成危害,同时其引起过大的地表沉降也会对地表造成危害。本文以重庆永荣矿业有限公司丰盛一矿开采工程为背景,运用有限元数值模拟软件MIDAS/GTS建立隧道断面开挖的数值模型,计算隧道开挖引起的地表沉降量。结果表明,随着埋深的增大,围岩破坏程度渐进扩大趋势,同时地表沉降量先减小后增大。在岩性较差的地层进行隧道的开挖,容易引起周围岩体的扰动,在强度相差较大的地层交界处其影响达到最大,进而出现大的变形或破坏;但如果交界的两个地层岩性相同或相近,则影响较小。     

Development in Information and Communications Technology (ICT) Statistics at the Australian Bureau of Statistics

This paper outlines the ICT statistical developments that the ABS has undertaken over recent years. These developments have been on both the supply side (ICT industry) and the demand side (use of IT by sector). The content of ABS ICT surveys has changed significantly over the last few years and are expected to develop further in line with industry changes and emerging policy needs.
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field.     

Value at Risk in the Suburbs: Eminent Domain and the Geographical Politics of the US Foreclosure Crisis

Several US counties and local governments have recently considered a novel solution to the foreclosure crisis. They plan to use eminent domain to compel the owners of mortgage debt—and specifically of private‐label mortgage‐backed securities—to sell the debt to the government at a price reflecting the loan's market value. The government would then restructure the debt and resell it to new investors. The plans are striking because—in contrast to both development‐driven eminent domain and the federal subprime bank bailout—they would force investors to assume asset devaluation and increased long‐term risk. Notably, the plans have emerged as an instance of financialization‐focused politics in suburbs and suburban cities of color, specifically majority‐black and ‐Latino/a suburbs. Local support for the plans, we argue, is rooted in the long‐term disinvestment of these ‘suburbs of exception', which became targets of subprime lending and eventually sites where the ‘financial exception' has been localized. But these demographic shifts, fragmentation and fiscal pressures have at the same time created a suburban political terrain in which the plans have gained their strongest political support.     

Towards a Theory of Serendipity: A Systematic Review and Conceptualization

Serendipity – the notion of making surprising and valuable discoveries – plays a major role in the success of individuals and organizations alike. Previous research has established the importance of serendipity and identified important individual- and organizational-level antecedents. However, the literature has been dispersed and the boundaries of the concept have been blurry, leading to a lack of conceptual clarity and structure, and thus limiting validity and managerial actionability. Based on a systematic literature review, I synthesize existing management-related research on serendipity and explicate the emergence and composition of serendipity in the organizational context. I first identify three necessary conditions that differentiate serendipity from related concepts such as luck or targeted innovation: agency, surprise, and value. Then, I draw from the literature on sensemaking, event-based theorizing, and quantum-based approaches to management to conceptualize the process of cultivating serendipity in the organizational context as a process of enabling potentiality and materialization, and develop a multi-level theory of (cultivating) serendipity. This conceptualization contributes to our collective understanding of how, why, and when (i.e., under what conditions) organizations can leverage the value in the unexpected, which opens up fruitful avenues for further research.     

Accountability of NGOs in Bangladesh A critical overview

NGOs in Bangladesh have been recognized as effective change agents in the socio-economic arena throughout the world. Their contributions in micro credit, non-formal education and primary health care are widely known. NGOs play a significant role in society. NGO accountability, as a result, has become a critical issue. NGO accountability in Bangladesh has been examined here in relation to patrons, clients and themselves. Of the three relationships only accountability to patrons is in a near satisfactory state. Accountability to clients is handicapped by lack of opportunities of beneficiaries to participate meaningfully in NGO policy making. Accountability to themselves is adversely affected due to the adherence to a strictly hierarchical system and the influence of founding and charismatic NGO leaders.     

Towards an Asian model of human resource management? A comparative analysis of China,Japan and South Korea

There has been much discussion regarding the possible decline and weakening of national systems of human resource management (HRM). Yet, culture and institutions are often cited as the major stumbling blocks to this outcome. Such constraints may dissipate in the analysis, particularly if ‘regional clusters’ are considered where geographic and cultural closeness and ‘openness’ to similar economic pressures exist. In such cases, it might be postulated that convergence in HRM will occur. We argue that China, Japan and South Korea represent such a cluster. This article examines these countries, to see if a degree of convergence is taking place and if it is towards an identifiable ‘Asian’ model of HRM. A model of change is presented that distinguishes between levels of occurrence and acceptance. Details of the development and practice of HRM in each country are then set out. The article ends with a discussion and implications section and a brief conclusion.     

Ansätze und Ergebnisse anglo-amerikanischer M&A-Forschung

Based on a review of established U.S. management journals (1995–2003), six schools of thought are identified within the Anglo-American M&;A research: “Capital Market”, “Principal/Agent”, “Industrial Organization”, “Organizational Behavior”, “Human Resources” and “Strategic Management”. The literature review shows that the definition of M&;A success, the methods applied, and insights from empirical research differ according to the respective school of thought. Empirical studies focus on the resource combinations of merger partners, the specific circumstances of merger negotiations, and on integration management as antecedents of merger performance. Unfortunately, empirical findings have not yet provided reliable explanations for M&;A success. Based on the current state of Anglo-American M&;A research, the authors discuss implications for business practice, identify research gaps, and propose areas for future research.     

Introduction of New Technology with a Sound Transition of the Input-Output Structure

We examine the general equilibrium repercussions associated with the introduction of new technologies, using the generalized Leontief system that allows technological substitutions. We show that an untested introduction of cost-increasing technologies in any industry may result in creating a non-productive technological structure that does not satisfy the Hawkins-Simon condition, following the autonomous dynamic adjustment process with structural transitions in the economic system. Therefore, we propose a practicable control scheme of introducing cost-increasing technologies that strictly avoids the creation of non-productive structures in all periods of structural transition, using the available information on the ex ante technological structure.     

The Creation of the Office for National Statistics

A new Office for National Statistics was created in the United Kingdom in 1996 following a series of developments designed to strengthen the relevance and integrity of statistics. This paper describes these fundamental changes and sets out a blueprint for future progress. It also sets current developments in the United Kingdom in an historical and international context.     

What helps? Women engineers' accounts of staying on

We have considerable understanding of the obstacles that women engineers encounter and the reasons that they leave the field, but we know less about what enables them to remain. Adopting an interpretivist approach, this article examines how a group of British women engineers in two FTSE 100 companies account for “staying on” in their male‐dominated work settings. We delineate four specific forms of help that facilitate women's retention in the field. We argue that exposure to help leads to women developing a habitus that enables them to continue working in engineering. To conclude, we draw on our findings to outline HR practices that will facilitate supportive relationships in the workplace and pave the way towards developing more positive organisational climates.     

论现代物流企业的发展观

物流业经过诸多年的发展目前已经成为最热门的行业之一,物流企业的注册数量也与日俱增,达到前所未有的规模。毋庸置疑,任何企业都希望自己迅速做强做大,并成为真正现代物流企业的典型代表,要实现这一目标一个首要问题就是要解决现代物流企业的发展观问题。