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1.
翁传源 《科技信息》2008,(9):135-135
在重大工程项目和高层建筑的施工过程中,大体积混凝土施工是工程的施工控制要点之一,需要从混凝土施工的部署、混凝土的原材选择和优化配合比、混凝土的供应、搅拌、测温、防裂控温养护等方面采取先进的施工技术和措施来确保混凝土的施工质量,避免因水化热和收缩引起的裂缝。大体积混凝土施工过程的主要技术要点可分为施工准备、施工措施、保温养护、温控监测等四大部分,在实际工程中,随着相关施工规范的不断落实以及工程经验的积累,施工单位在施工措施、保温养护、温控监测等阶段对工程质量的把握已经有了相当的经验.并形成了相对成熟的技术方案。然而,施工准备作为整个工程的前提,作为所有后续工作顺利进行的保证,单一性极强,在工程中未能形成系统的技术方案.由于准备工作存在不足或错误.往往给工程的施工造成混乱.本文结合广东某大型项目的大体积混凝土施工工程.对大体积混凝土施工中的施工准备进行阐述,提出了准备过程中技术准备、施工准备、组织准备的一些可供借鉴的方法。  相似文献   

2.
李冬梅 《科技信息》2009,(9):10-10,20
混凝土的冬季施工,随着施工高速化、结构大型化和建筑造型多样化的发展,施工质量和功能的要求也越来越高.加之无数经验教训,促使人们对混凝土的冬季施工越来越加以重视。文章主要从原材料、配合比、热工计算、混凝土的浇筑、运输及养护等几个方面.阐述了大体积混凝土在冬季施工的控制方法。  相似文献   

3.
顶山隧道二次衬砌施工模拟试验,是模仿隧道的实际地质条件和周边环境建造一个长14.4m,宽6.02m,高3.9m的隧道模型,其混凝土设计强度等级为C30。针对不同的部位分别采用普通混凝土、普通高性能混凝土、掺膨胀剂高性能混凝土、掺纤维高性能混凝土。模型施工的主要目的是,试验中低强度高性能混凝土的施工方法及各项混凝土性能,检测混凝土的抗裂性能。模型施工历时18d。  相似文献   

4.
介绍了PP改性纤维混凝土的有关性能实验,在水泥混凝土中掺加PP改性纤维后,混凝土抗弯拉强度、抗裂性等有了较大提高。在路面混凝土施工中掺入PP改性纤维后,混凝土拌合物的施工性能良好,抗弯拉强度在5.5~6.2MPa之间,满足设计要求。  相似文献   

5.
张卫东 《科技信息》2012,(21):371-371,410
近年来,随着城市建设的发展,高层、超高层钢筋混凝土建筑大量涌现,混凝土施工中的质量问题亦突出的显现出来。混凝土质量的好坏.关系到建筑物及构筑物的结构安全,关系到千家万户的生命财产安全。因此,解决常见的混凝土质量问题,在施工过程中对混凝土的施工进行综合控制.是不可忽视的问题。本文根据多年来的工作经验,结合工程中的现实问题,分析了混凝土施工中容易出现的质量问题的原因及施工中应注意的事项。  相似文献   

6.
混凝土保护层在设计施工中的问题探讨   总被引:1,自引:0,他引:1  
混凝土保护层直接关系到混凝土结构的耐久性,以往的结构设计和施工中考虑强度多而考虑耐久性少,轻视混凝土保护层的设计和施工。针对上述问题.对混凝土保护层在设计、施工中应注意的几个问题做了简要分析。强调指出,只有严格按有关技术条款和规范进行混凝土保护层的设计和施工,才能确保混凝土结构的耐久性。  相似文献   

7.
加气混凝土作为一种新型的墙体填充材料,具有容重小、强度低、吸水率高、收缩性大等优点.目前,由于工程应用中存在空鼓、开裂、剥落和墙体收缩裂缝等施工质量问题,在很大程度上限制了加气混凝土材料的发展与应用.为此,应采取提高混凝土的表面性能,加强砂浆与加气混凝土的粘结等施工措施加以解决.  相似文献   

8.
韩愈 《科技信息》2009,(19):263-263
沥青混凝土面层具有良好的力学性能和耐久性以及行车舒适性,适合于各种车辆的通行,并具有表面平整、坚实、无接缝、行车舒适、耐磨、噪声低、施工期短、养护维修简便,适宜于分期修建等优点,因此得到了广泛的应用。通过多年的沥青混凝土路面施工,积累了一定的经验.在此对沥青混凝土路面施工质量的控制要点进行探讨。1.沥青混凝土路面原材料准备在沥青混凝土路面工程施工的准备阶段,原材料的质量检查应当是质量控制工作的主要内容,因为原材料的质量是影响沥青混凝土路面质量的根本因素。同时,对石料、矿粉的选定还须考虑到采石场的产量。沥青混凝土路面施工具有大规模、机械化施工的特点,日生产量大,如果因为原材料的供应不足而影响施工日进度,这实际也对沥青混凝土路面的质量造成影响。  相似文献   

9.
本文分析了钢筋混凝土框架结构施工中梁柱节点箍筋施工,混凝土强度等级.混凝土保护层厚度和混凝土施工质量控制等工艺中存在的质量问题,并提出了相应的控制措施,供广大工程技术人员参考.  相似文献   

10.
方建华 《广东科技》2007,(10X):236-238
从沥青混凝土路面施工的全过程出发,对实际施工中的施工工序、施工工艺、质量保证进行了详细阐述.并针对施工中出现的问题提出了具体的处理措施。指出加强管理和组织施工,才能铺出高质量、高水平的沥青混凝土路面,创造成优良工程。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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