预应力在高墩托架预压中的应用

本文通过重庆忠垫高速公路杨家岭特大桥施工实例,介绍了在高墩连续刚构桥梁0#梁段施工时,应用预应力技术,对高墩托架进行预压的方法,并与传统堆载的预压法进行了比较。     

连续刚构高墩施工托架预压技术

大河边特大桥主桥为预应力混凝土连续刚构桥，主墩上部结构箱梁1-0-1＇#块段采用预埋牛腿托架法施工方法，文章介绍该桥施工中采用的预应力施载的托架预压技术。     

分离式桥现浇连续箱梁钢管支架施工方案

文章以陈家田分离式桥现浇连续箱梁满堂钢管支架施工为例，介绍了在山区软质地基上进行现浇预应力连续箱梁满堂钢管支架施工的总体布置方案，并通过支架力学检算验证了施工方案的可行性，同时阐述了支架地基处理、支架装拆及加载预压等施工过程。     

罗天乐大桥连续刚构0#块施工托架设计方法

文章介绍了罗天乐大桥连续刚构0#块施工托架的设计与计算方法，指出所采用的预埋牛角焊接型钢托架法具有取材方便、组装速度快、变形小、安全性高、经济适用等优点，适合高墩施工和无基础支撑条件的墩桩施工，可供同类型桥梁工程施工参考。     

浅谈满堂支架现浇预应力连续混凝土箱梁施工控制要点

本文结合永武高速公路A8合同段主线1号桥工程施工实践,介绍满堂支架施工现浇预应力混凝土连续箱梁的支架设计施工、支架预压观测、箱梁砼施工及安全施工措施等.对同类桥梁施工具有一定的参考价值.     

连续刚构高墩长悬臂0~#块托架设计与施工分析

文章以天峨龙滩特大桥引桥(72+135+72)m桥跨连续刚构为例,针对高墩长悬臂0~#块施工托架设计以及预压工艺难点问题,提出一种装配式托架结构以及高墩原位预压方式,并应用Midas Civil有限元软件对托架结构及预压进行仿真分析,验证托架结构的刚度、稳定性,避免了大量高空焊接作业且操作简便,具有良好的效益,可为相关类似工程提供参考借鉴。     

浅谈预应力施工中需要注意的细节问题

预应力施工是连续刚构的控制重点以及控制难点,直接影响到连续刚构的施工质量。文章以兰渝铁路128m连续刚构实体工程为依托,从预应力筋下料、穿束、张拉以及预应力管道压浆等方面,介绍了预应力施工过程中需要注意的问题及相关应对措施,供类似工程参考。     

连续梁桥0^#块施工支架方案优化设计

文章针对南充嘉陵江特大桥连续梁0#块支架前期设计方案存在的问题,提出了连续梁0#块施工支架优化方案,并通过技术性与经济性对比分析,验证了优化设计方案的合理性。     

浅谈连续梁桥0~#块施工方法和施工控制

连续梁桥0#块结构复杂、施工难度大,做好施工过程控制尤为重要。兰渝铁路南充联络线特大桥0#块施工采用了三角支架法,文章介绍了该施工工艺及施工控制要点,以供类似桥梁工程施工参考。     

浅析悬浇梁0#块托架反力预压技术的应用

本文以福寿高速公路西浦大桥工程为实例,对悬浇梁0#块托架采用反力预压的施工技术进行了研究和应用,经过实践证明该技术安全可靠、操作性强,有效缩短预压周期,降低施工成本,具有较好经济效益和应用前景。     

重庆朝天门长江大桥主桥钢桁架拱肋安装施工方案

文章介绍了重庆朝天门长江大桥钢桁架拱桥采用爬行吊机安装拱肋的施工方法,阐述了无支架缆索吊装钢铰线斜拉扣挂的施工工艺,为类似大跨度拱桥施工提供参考。     

大冲邕江特大桥承台钢套箱围堰施工关键技术

大冲邕江特大桥为不对称双塔三跨连续高低塔混凝土斜拉桥,桥塔承台长19．6m,宽18．5m,承台厚6m,采用双壁钢套箱围堰施工。文章介绍钢套箱围堰计算及施工技术,为同类桥梁提供借鉴参考。     

弯曲连续刚构桥剪力滞效应初探

箱梁的剪力滞后效应是大跨径连续刚构桥梁设计分析中较为复杂的内容之一，影响着桥梁结构设计的合理性。文章介绍了曲线箱梁的剪力滞计算方法，并结合泥溪沟2号大桥工程实例，通过建立三维实体有限元模型，对不同曲率的桥梁结构进行线性静力分析，得出曲线连续钢构桥任-截面剪力滞的分布规律。     

盐河特大桥主跨连续箱梁施工技术

盐河特大桥主桥是一座主跨为86m的大桥,采用V型支撑三跨预应力混凝土变截面连续箱梁。文章重点介绍该桥的主桥上部结构连续箱梁的支架现浇与挂篮悬浇施工技术。     

山区管架跨越管道施工技术

贵州开磷矿浆输送管道敷设最大坡度为10°,管道途经山坡,采用管架跨越结构,管道安装为高空作业,施工作业面狭小。介绍了施工遵循的原则、施工方案的确定、施工技术要点、脚手架验算等方面的内容,通过此方法,选择了合理的施工工序,充分利用了脚手架作业平台,保证了工程质量,加快了施工进度,有效解决了山区管架跨越管道问题。     

支架法在海中箱梁现浇施工中的应用

针对海中箱梁现浇施工中的工程量大、工期紧迫、悬臂法施工不能满足工期要求和施工难度大等问题，文章结合青岛海湾大桥箱梁现浇施工实践，介绍以钢管桩支撑作为承载基础，采用贝雷梁与碗扣式支架相结合的支架，成功地解决现浇箱梁施工难题的方法。     

浙江舟山西堠门大跨悬索桥施工技术

浙江舟山西堠门大桥为主跨1650m的两跨连续分离式钢箱梁悬索桥，其施工采用了较多的新工艺、新技术。文章从大桥基础、索塔、锚碇、索鞍、锚道、主缆、钢箱梁以及其附属设施等方面，介绍了舟山西堠门大跨悬索桥的关键施工技术及工艺。     

浅埋软弱破碎围岩隧道进洞施工技术研究

进洞一直是隧道施工的关键环节,而洞口工程的顺利完成是暗洞正常施工的前提。目前,采用超前管棚支护、超前小导管注浆等超前支护方式基本能够保证隧道顺利进洞,但是大部分隧道进洞后在洞口段均会出现初期支护沉降变形较大的现象。山西省高(平)-陵(川)高速公路郭家川2#隧道洞口段围岩极其软弱破碎,在隧道采用超前管棚支护顺利进洞后,为了防止洞口段初期支护再次出现较大的沉降变形,提出在洞口段采用联合支护的方案,即将洞口段初期支护的钢拱架与护拱连接,并加强初期支护钢拱架之间的纵向连接,实践证明此方案是切实有效的。分析对比表明,对于浅埋软弱破碎围岩隧道,联合支护方案能够有效地减小洞口段初期支护的变形量,保证隧道结构的稳定性,从而保证隧道安全、快速进洞。     

General Construction Technology Scheme of Tianshan Shengli Tunnel on Urumqi-Yuli Expressway北大核心CSCD

With a total length of about 22 km, Tianshan Shengli Tunnel on Urumqi-Yuli Expressway is currently the longest expressway tunnel under construction in the world. It adopts the construction scheme of "3 tunnels (2 D& B main tunnels and 1 TBM-driven middle pilot tunnel) + 4 shafts", which is characterized by great construction difficulty and high technical standard requirements. The tunnel construction is faced with technical challenges such as TBM passing through large fault fracture zones, long-distance construction ventilation in three tunnels, deep and large shaft construction and logistics organization in two-main tunnel construction assisted by middle pilot tunnel. In the parallel three-tunnel method design of Tianshan Shengli Tunnel, the TBM-driven middle pilot tunnel can not only play the role of advanced pilot tunnel, but also assist the construction of the two main tunnels and speed up the construction progress. For the middle pilot tunnel, the TBM excavation diameter is 8.4 m, and the initial support is designed as 100% force-bearing capacity in construction period, which can meet the requirements for two-way material transportation, ventilation and belt mucking in the pilot tunnel. Vault suspension scheme is adopted for the continuous belt conveyor, which can reduce the impact on the material flow organization in the cross passages. Multifunctional service vehicles (MSVs) independently developed by CCCC Group are used for the transportation of TBM materials and prefabricated inverted arch blocks, which can realize double-headed driving. TBM will pass through two large fault fracture zones F6 and F7. According to the stability of the surrounding rock at the tunnel face, the targeted treatment measures would be adopted. If necessary, the scheme of "steel segment + extruded concrete" shall be used for the initial support. In case of serious machine jamming or rock collapse, the heading expansion excavation method or bypass heading method shall be used. Tianshan Shengli Tunnel adopts phased forced ventilation option, and the ventilation mode is designed in stages with the change of tunnel construction stage. The fans and air pipes used are imported ones, and a ventilation management team is set up to strengthen ventilation management and ensure ventilation quality. Highly mechanized construction is used for the two D& B main tunnels, the application of equipment such as three-arm rock drilling jumbo and wet shotcrete machine is promoted, so as to reduce the number of workers and labor intensity, and improve work efficiency. The deep shafts of Tianshan Shengli Tunnel are constructed by short-section excavation and lining mixed operation method, and the initial support is lined by formwork pouring concrete, so as to realize safe and rapid excavation. According to the research results, the construction technology scheme for Tianshan Shengli Tunnel can meet the needs of tunnel construction. The research results can be directly used to guide the construction of Tianshan Shengli Tunnel, and provide reference for the construction of extra long highway tunnels in high-altitude areas. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved.