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钻孔灌注桩作为一种桩基础形式,其工艺日趋完善,目前被广泛应用于市政工程中。但钻孔灌注桩易受施工工艺、泥浆护壁、砼配合比、成孔灌注方法等诸多因素影响,稍有不慎或措施不严就可能造成质量缺陷甚至废桩,对整个工程的质量和进度带来直接的影响,给施工单位造成较大的经济损失和不良的社会影响,因此必须高度重视。 相似文献
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本文通过对泥浆护壁钻孔灌注桩常见施工质量问题的分析,并编制相应的防治措施;希望对泥浆护壁钻孔灌注桩常见的施工质量通病防治能有一些启示。 相似文献
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本文探讨泥浆护壁钻孔灌注桩施工质量控制管理,主要从准备阶段、成孔阶段以及水下混凝土施工几个方面全面讨论泥浆护壁成孔灌注桩施工管理要点. 相似文献
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旋挖成孔工艺是利用筒式钻头底部的斗齿,切削土体,并压入容器内,然后由钻杆提出筒式钻头,如此循环完成成孔作业。因此,旋挖钻机的成孔率速率大大提高,再加上旋挖钻机设备的特点,旋挖钻孔灌注桩的施工效率是传统钻孔灌注桩的5～10倍。由于旋挖钻孔灌注桩的特殊成孔工艺,它仅需要静压泥浆护壁,所采用的泥浆一般用膨润土、火碱、纤维素等配制,在孔壁不形成厚的泥皮：此外钻头多次上下往返,使孔壁粗糙,增强了桩土之间的咬合,大大提高桩的侧摩阻力。由于旋挖钻头可形成平底钻孔,有利于桩端阻力的发挥。旋挖钻孔灌注桩不需要循环泥浆护壁,当地层需要时,也仅采用制备的泥浆补充孔内,因此．不产生大量的泥浆,对环境污染小。同时泥浆重复利用率高,减少了泥浆的使用量。因此旋挖钻孔灌注桩有“绿色施工工艺”之称．对广东大唐潮州三百门电厂#3、#4机组（2×1000MW）扩建工程,针对工程地层条件,对施工中可能出现的问题作如下分析,并制定相应预防处理措施. 相似文献
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钻孔灌注桩在泥浆护壁的条件下,利用机械钻进形成桩孔,采用导管法进行混凝土浇注的施工方法。针对钻孔灌注桩施工中质量缺陷与处理措施进行了论述。 相似文献
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在钻孔灌注桩施工中发现存在地下溶洞,出现掉钻,孔内泥浆在短时间内大量流失,孔壁坍塌现象;采用注浆的方法进行处理,保证钻孔灌注桩的正常施工。 相似文献
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近年来,随着桥梁跨度和高层建筑荷载的不断增加,对钻孔灌注桩承栽性能的要求也越来越高。从钻孔灌注桩的施工工艺、桩底沉渣和泥浆护壁这三个方面对其承载性能进行研究,期望能够为提高钻孔灌注桩的承载性能给予一定的帮助。 相似文献
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钻孔灌注桩的成孔方式有冲击成孔,贝诺特法成孔,泥浆循环回转钻进成孔等方法。根据实际施工中的总结,本文主要谈在泥浆循环回转钻进成孔灌注桩施工的质量控制要点。 相似文献
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桩基础是建筑工程中常采用的基础形式之一.泥浆护壁钻孔灌注桩作为桩基础的一种类型,由于它具有对地层的适应性强(能在各种土层中成桩),承载力大,造价低,以及低噪音,低振动等优点,目前在沿海地区(如:上海、天津等地区)地基处理中应用十分广泛,广泛地被用于大型厂房,(超)高层建筑,桥梁、港口等建设.泥浆护壁钻孔灌注桩作为地下隐蔽工程,在施工过程中影响质量因素较多.本文就混凝土灌注桩施工过程中,应如何加强质量控制,结合本人在工作中的经验对泥浆护壁钻孔灌注桩的质量控制提出一些粗浅看法. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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《中国科学院院刊(英文版)》2008,22(1):13-14
Aresearch project on the greenhouse cultivation of Swertia chirayita Buch Ham, a popular herbal drug used by the Tibetan people against liver and gallbladder diseases, recently passed the acceptance check by a panel of experts under the auspices of Qinghai Provincial S＆T Bureau. The feat was accomplished by researchers from the Lanzhoubased CAS Northwest Institute of Plateau Biology. 相似文献
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The research into the origins of domestic animals is of significance not only for understanding their development per se but also for making clear the human society evolution. Although there are evidences to show that pigs were independently domesticated in a variety of places throughout the world the detailed scenario of the origin dispersal of domestic pigs in East Asia remains unclear.…… 《中国科学院院刊(英文版)》2008,22(1):7-7
The research into the origins of domestic animals is of significance not only for understanding their development per se, but also for making clear the human society evolution. Although there are evidences to show that pigs were independently domesticated in a variety of places throughout the world, the detailed scenario of the origin and dispersal of domestic pigs in East Asia remains unclear. 相似文献
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Among the galaxy of research development organizations in northwest Beijing's Zhongguancun district known as China's Silicon Valley two are especially well-known to IT researchers: Microsoft Research Asia 《中国科学院院刊(英文版)》2008,22(1):47-49
Among the galaxy of research and development organizations in northwest Beijing＇s Zhongguancun district, known as China＇s Silicon Valley, two are especially well-known to IT researchers： Microsoft Research Asia （MSRA）, and, within a few blocks on the other side of the street, the CAS Institute of Automation （CASIA）. While most people in Chinese scientific organizations strive to move to a large foreign counterpart, Dr. Stan Z. Li （LI Ziqing） moves against the stream. 相似文献
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Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献
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《中国科学院院刊(英文版)》2014,(3):212-213
<正>In February 2014,the 30th Chinese Antarctic inland expedition team reported that they have successfully conducted the seeing measurement at the Antarctic Taishan Station using a Differential Image Motion Monitor(DIMM)developed by the Nanjing Institute of Astronomical Optic and Technology(NIAOT),Chinese Academy of Sciences.In astronomy,seeing is a physical parameter that describes the irregular movement and blur of the star 相似文献
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XIN Ling 《中国科学院院刊(英文版)》2014,(4):270-271
Amassive overhaul is coming to the Chinese Academy of Sciences （CAS）. To straighten its ＂fragmented, inefficient research＂, the academy has decided to restructure its 104 institutes for better teamwork. 相似文献
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SONG Jianlan 《中国科学院院刊(英文版)》2014,(4)
<正>DNA demethylation in mammalian zygotes,a biochemical process through which the parental genomes let go the epigenetic marks from their"past lives"to obtain totipotency,has long fascinated biologists:how does it happen?A joint team at the CAS Shanghai Institutes for Biological Sciences tells a surprising story. 相似文献
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China is one of the fastest growing economies worldwide. Are science and research also in the fast lane? We talked with LUO Yuan, scientist at the Institute of Coal Chemistry in Shanxi, and Axel Mosig, Professor at Ruhr University in Bochum, who has first-hand experience working and living in China. 相似文献