一个顶管法穿越高速公路的施工方案

广州地铁二号线要穿越华南路,华南路是一条高速公路,施工时地面交通不能中断,本文建议采用顶管法穿越.全文共分6段1.概述;2.工作坑;3.顶力计算;4.后背土抗力计算;5.减阻;6.其它.该文虽然只是一个施工方案,但对顶管法考虑的尚属全面,可供参考.     

Effect of building stiffness on tunnelling-induced ground movement

The progressive response of two–three storey masonry buildings to bored tunnelling on the Jubilee Line Extension in London is investigated in order to determine the effect of building stiffness on tunnelling-induced ground movement. The masonry buildings, at Moodkee Street and Keetons Estate, were affected by tunnelling with earth pressure balance machines on Contract 105 of the Jubilee Line Extension. Bending deformations and axial strain induced in these structures are compared to greenfield ground deformations and strain in order to infer the effect of building stiffness. The modifying influence of the stiffness of these buildings on ground movement is interpreted using the Potts and Addenbrooke [Potts D.M., Addenbrooke, T.I., 1997. A structure’s influence on tunnelling induced ground movements. Proc. Inst. Civ. Eng. Geotech. Eng. 125 (2), 109–125] method, which is based on a series of finite element analyses. The inferred building stiffness that can be used for design purposes with the Potts and Addenbrooke method is compared to an estimation for a Class A [Lambe, T.W., 1973. Predictions in geotechnical engineering. Geotechnique 23 (2), 149–202] prediction exercise by Mair and Taylor [Mair, R.J., Taylor, R.N., 2001. Settlement predictions for Neptune, Murdoch and Clegg Houses and adjacent masonry walls. Building response to tunnelling – case studies from construction of the Jubilee Line Extension, London. In: Burland, J.B., Standing, J.R., Jardine, F.M. (Eds.), Projects and Methods, vol. 1. CIRIA SP200, pp. 217–228 (CIRIA and Thomas Telford, 2001). ISBN: 0 7277 30177] using the same method. As a result an alternative approach is proposed for estimating the relative bending stiffness of masonry structures for future use with the Potts and Addenbrooke method when making simple predictions.     

The process of social alignment and misalignment within a complex IT project

Project management is more efficient and effective when project stakeholders are socially aligned on what the project objectives are and how they should be achieved. This outcome occurs because social alignment reduces the friction amongst stakeholders each time a project management decision is made. Yet, how social alignment develops or dissolves over time in a complex project is unknown. This research develops a dynamic model of social alignment and misalignment, and it identifies some of the project controls that appear to affect their development. Drawing on interview and observational data from 17 respondents involved in a complex health-IT project over a two-year period, we show that social alignment and misalignment involve eight stages – separation, disrespect, lack of cross-discipline participation and social misalignment through to learning, respect, cross-discipline participation and ultimately, social alignment. The research has implications for how researchers theorize social alignment in complex projects and how practitioners can facilitate its development.     

Client versus contractor perspectives on project success criteria

There are case studies that suggest an obstacle to effective client–contractor working relationships is a failure to agree on measures of success and a failure by the client to consider the needs of stakeholders, though there has been little systematic research in this area. The aim of this paper is to report the findings of an empirical study that compares the measures of success emphasised as important by client and contractor organisations and the extent to which differences of emphasis is translated into project management practice. The results show that contractors put more emphasis on minimizing project cost and duration, whilst clients put more emphasis on satisfying the needs of other stakeholders. However, in their project management practice clients show no stronger focus on meeting stakeholder needs than contractor organisations. Implications of these results are discussed in the context of possible barriers to effective client–contractor working relationships.     

大型地下管道暗挖施工结构设计探讨

本文对大型地下管道采用不开槽暗挖施工时结构承受的荷载、内力分析以及构造处理等，分别作了介绍和探讨，供同类工程结构设计参考。     

Numerical simulation of the swelling behaviour around tunnels based on special triaxial tests

This paper is to contribute to the understanding of the behaviour of tunnels in swelling ground. An Italian case study of a tunnel, collapsed due to swelling of a stiff clay, is taken as an example. The stress paths during excavation of elements of ground around the opening are computed in order to evidence the significant difference to that reproduced by usual swelling tests in the laboratory. An innovative triaxial testing procedure is developed and the stiff-clay tested. A numerical simulation of the swelling phenomenon induced by the excavation of the tunnel, based on the experimental results obtained, is then compared to site observations.     

下穿式立交排水优化设计

城市下穿式立交由于其最低点较低、引道纵坡较大等结构上的特点,其排水系统较为复杂,每遇暴雨极易发生积水,严重影响交通安全,故其排水要求高于一般的雨水系统。本文介绍了下穿式立交排水系统的作用和特点。以厦门市海新路二期为例并结合工程设计经验,笔者对下穿式立交排水方式的确定、设计参数取值的合理性、优化雨水收集系统、采取合理的地下水处理措施、雨水提升泵站选址及优化泵站工艺流程等设计要点进行了较为详细的探讨,为现阶段国内优化下穿式立交排水设计提供依据。     

An experience of tunnelling in mudstone area in southwestern Taiwan

Many tunnels will be constructed in southwestern Taiwan in the upcoming decade to meet the huge demands of transportation, energy and water infrastructure projects. Mudstone strata cover more than a 1000 km² area, consisting mainly of massive mudstone or alternation of mudstone and sandy layer, exhibiting unfavorable geological and hydrological characteristics, making it extremely difficult for tunnelling. This paper presents the lessons learned from three tunnelling projects in the 1990s in a mudstone area. In addition to discussing the rock behavior in the vicinity of tunnel and its failure patterns, the monitoring data during tunnelling are presented as well. Finally, the effective method of design and construction are recommended for tunnelling in mudstone area.     

A study on the effects of overlying soil strata on the stresses developing in a tunnel lining

Shield tunnel lining in soft ground is usually designed based on empirical and analytical methods. These methods are convenient and easy to use; however, they are based on simplifying assumptions related to soil homogeneity around and above the excavated tunnel. The effects of overlying stiffer layers on the tunnelling induced settlement has been investigated by several researchers and was found to significantly influence ground movements. This study evaluates the effects of overlying stiff layers above a tunnel excavated in soft ground on the stresses developing in the tunnel lining. Laboratory investigation is conducted to study how the presence of these layers influence bending stresses in a model tunnel constructed in soft clay and overlain by a coarse sand layer located at different heights above the tunnel. Validation using the experimental results, elasto-plastic finite element analyses are then performed to explain the role of the relative stiffness between the overlying layer and the soft soil deposit hosting the tunnel. Depending on the thickness and location of the overlying stratum, the presence of a stiff layer above the tunnel can have a significant impact on the stresses developing in the tunnel lining.     

The thermal mechanism of warm in winter and cool in summer in China traditional vernacular dwellings

Yaodong is one representative of western China vernacular dwellings. Its indoor thermal environment is cool in summer and warm in winter. This study interprets the characteristic of warm in winter and cool in summer in such a dwelling by measuring the indoor, outdoor and wall’s temperatures in winter and summer. The human thermal comfort theory is used to evaluate thermal environment, and the periodic heat transfer mechanism is used to analyze the thermal transfer through the wall. The results show that the Yaodong thick wall effectively damping external temperature wave and keeping steady inner surface temperature are the chief causes of warm in winter and cool in summer in Yaodong, which lays a scientific basis for low energy building design.     

Landscapes in change—opposing attitudes in Saaremaa, Estonia

The paper explores how different stakeholders understand landscapes and which could be their role in planning and landscape change. The focal emphasis of the study lies on the values of Saaremaa Island. Local farmers and schoolchildren were interviewed and questioned to find out their perceptions and expectations about the landscapes. A media analysis was used to study how these understandings were represented in newspapers. The results reveal an alarming situation where the most valued landscapes experience signs of degradation and disappearance. The divergent goals, and concurrently, the varying valuations among different actors should be taken into account in landscape planning projects.     

Project governance and stakeholders: a literature review

Despite the importance of stakeholders in project governance, project management literature lacks from an inclusive framework which defines the roles, relationships and positions of internal and external stakeholders inside and outside of the organization's governance structure. This paper has the purpose to report a review on project governance literature to draw attention to the context within which the stakeholders are positioned, to extract their roles and relationships inside and outside of the organization and to develop new avenues for research regarding stakeholders in project governance. The conducted thematic analysis reveals that there are three contexts influencing organization's approaches towards stakeholders: success, megaprojects and ethics. The developed conceptual framework illustrates that organizations are in direct contact with external stakeholders at the organizational level and project level. Strategic decisions made at the organizational level are operationalised at the portfolio level and influence the approach towards external stakeholders at the project level. Considering the lack of theories to support general doctrine of stakeholder theory, this research suggests that future governance researchers adopt a broader view in selection of theoretical lenses in order to include the social and psychological aspects of the management of external stakeholders.     

Stakeholder management influence on trust in a project: A quantitative study

This article aims to analyze the influence of stakeholder management on trust in project environments. Data was collected from 130 project professionals in companies from several national and multinational segments operating in Brazil. PLS-PM was applied for treatment and for data analysis. The results show that the relational stakeholder management influence on the three types of trust is relevant and significant. Therefore, it is important that the project manager not fail to consider actions such as communication with empathy as of the beginning of the project.     

Urban underground space: Solving the problems of today’s cities

The world-wide trend of increased urbanisation creates problems for expanding and newly-developing cities alike. Population increase leads to an increased demand for reliable infrastructure, nowadays combined with a need for increased energy efficiency and a higher environmental awareness of the public. The use of underground space can help cities meet these increased demands while remaining compact, or find the space needed to include new functions in an existing city landscape. In many cases, underground solutions to urban problems are only considered if all other (above ground) options have been exhausted. When underground solutions are considered and evaluated from the planning or initial project stages onwards, more optimal solutions will become possible.Use of the underground is not limited to large scale infrastructure projects. This paper also shows innovative use of the underground for commercial and residential use, storage, water conveyance and treatment, and heritage conservation, and highlights how use of underground can bring more optimal solutions for urban development.     

Regulating Plastics Waste,Stakeholder Engagement and Sustainability Challenges in South Africa

In May 2003, the South African government enacted regulations banning the production of thin-film plastic shopping bags. The government advocated that such thin-film plastic shopping bags were indiscriminately discarded because they had no economic and recycling value. However, in as much as the regulations led to significant reductions in plastic shopping bags in the environment, the law resulted in severe unintended negative consequences, as jobs were lost with some businesses in the plastic shopping bag manufacturing sector closing down. The paper also reveals that key stakeholders, such as industry, business and labour, lobbied against the introduction of the regulations but without success. On average, business went down by about 83% with a conservative 25% reduction in employment. Drawing insights from the Irish and Australian experiences, this paper critically reviews sustainability debates and responses surrounding environmental regulation and business, with a special focus on the Plastic Bag Regulations in South Africa. Lessons learnt are presented with the intention to provide insights for future waste product or other environmental regulation initiatives in South Africa and elsewhere in the region.

Assessing the ability of rock masses to support block breakage at the TBM cutter face

In order for tunnel boring machines to efficiently cut or break rock, it is necessary that the block of rock in contact with the cutter be adequately supported by the surrounding rock mass. This support is provided by the interlocking of blocks and the friction of the surfaces. If blocks are inadequately supported or become free without breakage the result can be jamming at the TBM face. Such blocky ground conditions are typically assessed according to the spacing and orientation of discontinuities (including joints) within the rock mass, typically using a rock mass classification system. In laboratory tests on cuttability or abrasivity of rocks, test samples are typically supported securely in a frame or jig. Numerical models of rock breakage also assume boundary conditions in which the sample is completely supported. Therefore the applicability of the results from laboratory and numerical studies depends on the same degree of support of blocks in the ground. The conditions required to adequately support a block for breakage are investigated and related to rock mass parameters, in particular, the three-dimensional patterns of discontinuities. A rock mass can be capable of providing adequate support to a block of rock such that the cuttability is adequately described by conventional methods. However, there are some rock mass conditions where support of blocks is not well developed, potentially resulting in otherwise unexpected poor TBM progress or jamming of TBM with loose blocks. Three-dimensional discontinuity patterns can be assessed using stereographic methods or borehole (α–β) methods. It is proposed that problematic conditions may occur where: two or more oblique (α between 20° and 70°) discontinuity sets are present (and over-represented relative to a uniform distribution); one or more of these discontinuity sets are dipping into the opening (β = 180° ± 90°) and additional discontinuities (in sets or randomly oriented) are present to form complete tetrahedral wedge blocks.