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盾构隧道下穿铁路工程风险及对策 总被引:1,自引:0,他引:1
结合杭州地铁一号线下穿铁路艮山门辅助编组站盾构隧道工程,对其可能出现的风险进行了研究分析,提出了相应对策,并对盾构下穿施工参数提出了建议;针对可能出现的轨道过大变形,提出了对盾构穿越区采用分块加固的措施,并对加固后的效果进行了分析。 相似文献
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针对国内深厚软土地区盾构下穿改扩建堤坝变形安全控制问题,文章依托上海某典型软土盾构隧道下穿待改扩建堤坝工程,通过对比不同加固方式确定了真空联合堆载预压加固法,现场实测了真空联合堆载预压加固堤坝期间地层变形和孔压变化规律以及盾构下穿期间改扩建堤坝表层变形和隧道自身变形。结果表明:采用真空联合堆载预压加固方法可较好地控制盾构下穿改扩建堤坝的施工风险,真空联合堆载预压法对常规埋深盾构隧道下方约2倍盾构直径范围内的软土有加固效果,双曲线经验法能较好预测软土地区老旧大堤预压加固作用下的地基沉降,盾构穿越预压加固的大堤引发的固结变形沉降较小。 相似文献
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当盾构隧道近距下穿铁路桥梁结构物时,为保证既有铁路桥梁的运营安全,工程中通常采取一定的加固防护措施来控制铁路桥梁结构物的变形。文章以洛阳轨道交通1号线盾构隧道下穿东北联络线特大桥工程为背景,利用有限元软件ANSYS对既有铁路桥梁结构物的加固防护措施进行对比分析。研究结果表明,盾构掘进过程中其最大影响位移可能出现在施工过程中而并非完全贯通后;采用注浆加固与隔离桩防护措施对控制桥梁墩台及桩基位移均可取得一定的效果,但不同方向的控制效果存在较大差异,而且两种工法在控制位移的效果上也略有差异。 相似文献
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以福州地铁5号线盾构下穿在建福厦高铁为工程背景,针对软土地层小半径曲线盾构隧道下穿高铁高填方路基交叉施工工程的特殊性,利用现场监测数据对交叉施工全过程展开分析,研究该类工程地基加固效果及施工变形规律。结果表明,该工程若采用预应力混凝土管桩进行地基加固,后期地铁盾构施工不具备施工条件,需施作桩板结构进行地基处理;采用桩板结构对软土区域进行加固处理后,实测数据中最大地表沉降量为5.6 mm,为地表沉降控制值的18.67%,在可控范围内;提前进行地基加固后,当盾构隧道下穿施工时,路基不同位置处仅发生微小沉降,说明桩板结构加固对交叉施工变形有很好的控制效果;随着路基填筑高度增大,各层土压力值整体呈增大趋势,各层土压力变化速率呈“双峰曲线”,路基中间位置的土压力值比靠近两侧的土压力值大;盾构隧道下穿前,桩板结构混凝土支撑轴力的变化大致可分为“线性增长—过渡—再增长—稳定”4个阶段,当盾构下穿后,混凝土支撑轴力有小幅增大,后期逐渐趋于稳定。从监测数据分析可以看出,桩板结构的加固效果显著。 相似文献
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浅谈盾构下穿建筑物掘进参数控制 总被引:1,自引:0,他引:1
文章结合深圳地铁2号线2222标盾构机下穿景煜小学、翠海幼儿园等建筑物的工程实例,研究分析了盾构隧道下穿施工对城市建筑物的影响机理及变形控制基准值,提出了相应的盾构机下穿建筑物施工的掘进参数和控制地层沉降的技术措施。 相似文献
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盾构机在未经加固的软土地层中近距离下穿正在运营中的靥#线隧道,对其周围土体变形状况、档机理以及地层后期沉降的研究,提出了进行有效控制的施工方法及参数,解决了盾构近距离穿越邻近地下构筑物的技术难题,为今后的类似工程提供经验借鉴. 相似文献
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Ingmar Andrasson 《先进运输杂志》1998,32(1):23-34
A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996. 相似文献
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AbstractDespite a concentration of container traffic in the southeast of the UK over the last few decades, regional ports are attempting new development strategies to capture or retain specific traffic segments. These include intra-European short-sea traffic and a potentially increasing feeder market. These trends are reflected in the movement of different container types, which result in a number of planning challenges related to changing infrastructural and operational requirements. This paper uses highly disaggregated data on container type movements to address three issues that can inform these planning challenges. First, the imbalance of trade resulting in empty container repositioning; second, the requirement for gauge-cleared rail routes to cater for the increasing proportion of high-cube containers; and third, the specialisation of European short-sea traffic at secondary UK ports. The results reveal the disproportionate repositioning of empty containers at Scottish ports and the importance of 45?ft, high-cube and pallet-wide containers at regional ports, highlighting their focus on intra-European short-sea traffic and raising difficulties relating to their lower quality of landside infrastructure (particularly rail) in comparison to the large south-eastern ports. The potential repercussions on hinterland infrastructure development raise questions about both public and private sector responses to regional port development. 相似文献
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This research examines the problem of route bus specification and vehicle manufacturability. In order for bus operators to provide transport services, a range of vehicle configurations must be available from bus manufacturers, generating variety which has a negative impact on the manufacturing process. Larger part inventories, uncontrolled labour tasks and more troublesome maintenance are known impacts of this variety. This research identifies the functional necessities in route bus interior design and reduces the problems in bus manufacture and operation caused by specification diversity by proposing a modularised system of bus design. In particular, it makes recommendations as to how bus configuration should be carried out, ensuring an optimum mix of operational and manufacturing needs:
- 1.Determine user needs before the bus specification process.
- 2.Designs to be developed by the manufacturer in response to user needs.
- 3.This design should be standardised where possible, as suggested by the user needs.
- 4.Where user needs dictate product variations, apply a mass customisation approach to accommodate these needs.
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管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一(各因素的分值范围都是0~100分),为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。 相似文献
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In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector. 相似文献
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The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side. 相似文献
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Steven I. Chien 《运输规划与技术》2013,36(3):211-227
A mathematical model is developed in this paper to improve the accessibility of a bus service. To formulate the optimization model, a segment of a bus route is given, on which a number of demand entry points are distributed realistically. The objective total cost function (i.e. the sum of supplier and user costs) is minimized by optimizing the number and locations of stops, subject to non‐additive users' value of time. A numerical example is designed to demonstrate the effectiveness of the method thus developed to optimize the bus stop location problem. The sensitivity of the total cost to various parameters (e.g. value of users' time, access speed, and demand density) and the effect of the parameters on the optimal stop locations are analyzed and discussed. 相似文献
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David A. Hensher 《Transportation》1987,14(3):209-225
The established ownership mix of urban bus operations in Australia provides a unique opportunity to investigate the productivity differences between public and private bus service supply. Using duality theory in economics which links economic indices of factor productivity to the cost structure of a firm, we develop empirical measures of total and partial productivity of inputs, and adjust the differences for the effects of ownership status and operating environment. The evidence supports the notion that private supply of public passenger transport in general has performed more efficiently in the past than public supply, although the differences in productivity need not continue in the future. 相似文献