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1.
吕大为  朱晓菲 《科学技术与工程》2005,5(21):1683-16841689
现浇混凝土空心楼板施工中,通过空心管肋间钢筋骨架和抗浮筋对空心管材定位,混凝土浇筑顺序控制检查,保证现浇混凝土空心楼板的质量。  相似文献   

2.
雷鸣 《甘肃科技》2016,(15):90-92
宝兰客专是连接西北与内地高铁通道的关键工程,针对诸多不利条件和工期紧任务重的难点,在对高铁桥梁施工的重要环节包括承台大体积混凝土施工时,采用对应的技术措施,以保证混凝土浇筑和养护质量,攻克对工程建设安全、质量、工期、环境保护等影响重大的技术难题。从社棠渭河特大桥连续梁大体积混凝土施工的施工前期准备、桩头处理、钢筋制作安装、冷却管及测温元件安装、模板安装、混凝土浇筑、养护与拆模、基坑回填等方面进行控制,达到大体积混凝土施工质量要求的目标,确保后续工程的顺利进行。  相似文献   

3.
王万通 《科技信息》2008,(10):98-98
文章对影响混凝土浇筑质量的薄弱环节进行了分析,提出应从混凝土搅拌质量、混凝土浇筑时模板支护的质量控制和对钢筋保护层的混凝土浇筑的厚度,按照标准进行质量控制,以确保混凝土浇筑的质量。  相似文献   

4.
大断面深埋高水压盾构隧道实测内力反算与分析   总被引:1,自引:1,他引:0  
结合南京地铁3号线大直径盾构隧道工程,对隧道管片钢筋应变进行了现场测试,基于既有的管片内力反算方法,考虑混凝土非线性性质及管片接头,提出了适用于深埋高水压盾构隧道的内力改进算法,并对改进算法反算内力与结构设计计算内力进行了对比分析.结果表明:改进算法更能反映管片的实际受力状态,更适用于荷载模式复杂且接头传力机制多变的大断面深埋高水压盾构隧道;采用设计方法计算的深埋高水压盾构隧道管片及接头内力与改进算法反算内力的分布规律基本一致,但在量值上具有一定的差异;采用设计方法计算的管片及接头轴力为改进算法反算轴力的1/2左右,反算的管片弯矩在拱底位置与惯用法计算弯矩接近,在拱腰及拱顶位置与梁-弹簧法更为接近,反算的接头弯矩大于梁-弹簧模型计算接头弯矩.研究成果可为大直径深埋盾构隧道设计提供参考.  相似文献   

5.
混凝土管片裂纹是目前施工比较难克服的质量通病之一,文章针对盾构管道工程小体积管片施工技术的重、难点,结合有关专家的意见进行归纳,结合北江盾构穿越工程管片施工过程中的实际经验。介绍了盾构管片施工过程中不同裂纹类型、形成原因及控制重、难点,对关键工序及关键工艺进行重点介绍,供在生产过程应用。  相似文献   

6.
地铁盾构隧道30°斜穿地裂缝的物理模拟试验   总被引:1,自引:0,他引:1  
为了研究30°斜穿地裂缝的盾构隧道管片衬砌结构在地裂缝影响下的变形破坏模式和影响规律,从西安地铁盾构隧道工程背景和西安地裂缝地质环境出发,根据相似理论设计了盾构隧道管片衬砌结构模型试验的相似常数,对模型混凝土、模型钢筋、结构围岩、模型管片及其连接螺栓参数等进行了设计.该结构模型试验能对结构钢筋、混凝土进行应变测量,对结构接触土压力和结构外围土压力、结构内部收敛位移、模型顶表面土体变形等进行观测.借助地基沉降试验平台,通过自锁式千斤顶的缓慢下降,实现对地裂缝上盘相对下降的模拟,地裂缝的活动速率和错动量通过工控机控制自锁式千斤顶的运行速率和行程来实现.试验结果表明:该试验设计满足地裂缝活动下30°斜交盾构隧道管片衬砌结构变形破坏模式和破坏范围研究的需要,能实现模型试验目标;地基沉降试验平台能较好地模拟地裂缝的活动.  相似文献   

7.
文强  郭伟 《广东科技》2011,20(22):166-167
本文比较详细地介绍了南京地铁3号线、10号线过江隧道盾构钢筋混凝土管片的固定式生产工艺,并研讨了管片生产中常见的几个错误认识.  相似文献   

8.
为评价钢纤维掺入对盾构隧道混凝土管片局部力学性能的改善情况,采用通用有限元软件AD INA,分别对盾构隧道钢纤维混凝土管片在千斤顶顶力作用及管片接头在正常运营阶段的开裂荷载、应力分布及裂缝分布进行了三维有限元数值试验.结果表明:掺入钢纤维能有效改善管片表面、手孔和螺栓孔部位的局部力学性能;钢纤维混凝土管片的初裂荷载比普通混凝土管片提高13.3%~22.7%,说明管片的抗裂性能有较大提高.  相似文献   

9.
预测和可视化监测异形盾构管片混凝土裂缝宽度和开展规律对站立式原型异形盾构管片加载系统的研发以及后续的异形盾构管片优化设计至关重要.通过梁荷载试验完善了体积率为2%的CF50钢锭铣削型钢纤维混凝土最大裂缝宽度理论公式,同时创新性地在原型管片结构试验领域引入非接触式应变光学测量系统,对管片拱顶内弧面关键区域进行裂缝实时监测.研究结果表明,基于三维数字图像技术(DIC-3D)可定义管片裂缝出现时机判定和裂缝宽度计算方法.管片裂缝宽度经历了初始、稳定和加速等三阶段发展过程,最终确定出异形盾构衬砌结构极限覆土深度为18.5 m.梁荷载试验所获最大裂缝宽度理论公式中的相关设计参数是有效的,未来可结合壳-弹簧模型计算管片内力结果进行异形盾构管片裂缝宽度的科学预测.  相似文献   

10.
穆玉国  刘新力 《科技信息》2009,(25):286-286,320
所谓后张法预应力箱梁就是先浇筑混凝土.后张拉钢绞线的施工工艺。要生产出合格的箱梁,应有效控制的环节是:原材料、水泥混凝土配合比、水泥混凝土的拌合、浇筑、普通钢筋骨架的制作、施加预应力。制造过程中的每一道工序均需满足设计和规范要求。  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.
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   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
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   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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