首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
近年来,随着大批的高层和超高层建筑的建设,开发商为提高建筑用地率,加之国家有关规范对基础埋置深度和人防工程的要求,多层、高层、超高层建筑地下室的设计必不可少,有的地下建筑甚至有三四层,深的达十多米,于是,地下建筑开挖时的深基坑支护成为一个必要的施工过程。目前的建筑工程深基坑支护设计和施工还存在着很多不够完善的地方。本文针对建筑工程深基坑支护设计和施工现状,进而提出了加强建筑深基坑支护的质量控制。  相似文献   

2.
为了将原位载荷试验应用于地基沉降计算,以延安地区黄土填土工程为实例依托,采用弹性理论中的应变影响系数和完全侧限点的应力应变关系理论,推导了利用载荷试验结果计算地基压缩模量的方法。研究结果表明:符合完全侧限应力状态的点位于载荷板中心点下0.834倍荷载板半径R处;将载荷试验结果中荷载P乘以0.737、荷载板沉降S乘以0.522与荷载板半径R的比值,可将载荷试验的P-S曲线转化成单向压缩的应力-应变曲线,进而可以计算出压缩模量;由该文方法计算的压缩模量均值与室内试验测试结果均值一致,两者平均值的差异仅为5.53%;由于原位测试避免了对土样的扰动,所以得到的压缩模量的离散性低于室内试验测试结果,方差减小了57.2%。研究成果可为压缩模量的测试方法和地基沉降计算方法的拓展提供参考。  相似文献   

3.
非对称超载条件下深基坑支护结构的变形分析   总被引:1,自引:0,他引:1  
文章以苏州地铁1号线深基坑工程为研究背景,采用GTS软件对基坑支护体系进行了有限元分析;考虑支护结构与土体的共同作用,计算和分析了非对称超载条件下支护结构的内力和变形,并与对称超载条件下的计算结果进行对比,得到了非对称超载条件下支护结构内力和变形的分布规律。计算和分析结果表明:非对称超载状态下,基坑支护体系超载侧支撑轴力略大于对称超载条件下的支护结构,但超载侧的位移较大,基坑的稳定性处于最不利的状态。研究结果将有助于提高深基坑设计水平,为类似工程的设计、施工和研究提供必要的数据。  相似文献   

4.
随着我国经济的快速发展,国内建筑也逐渐向大型化方向发展,高层建筑的深基坑支护技术得到了前所未有的重视,且已成为当前高层建筑的主要施工方法。深基坑的支护技术可以保证高层建筑周边环境的安全,是一种可以支挡、加固的保护措施,任何高层建筑都需要具备良好的根基基础,只有具备了坚固的根基,高层建筑才可以不断平地而起。该文通过介绍超高层建筑深基坑支护工程存在的几点问题,指出了深基坑支护技术的具体实施方法。  相似文献   

5.
王少军  由旭蕾 《科技信息》2012,(31):407-407
近年来,随着我国城市化建设进程的不断加快,从而带动了建筑业的发展,各类建筑工程与日俱增,其中又以高层建筑居多,这主要是因为我国建筑用地稀缺以及人口众多,导致了建筑向高层和超高层结构发展。由于高层建筑楼高层多,其结构稳定性非常重要,这给基坑支护提出了更高的要求。为了满足高层建筑的要求,基坑工程逐步向纵深方向发展,现如今深基坑支护工程越来越多。为了进一步确保深基坑工程的整体质量,就必须采取合理的支护技术。基于此点,本文就建筑工程深基坑支护技术的有效措施进行浅谈。  相似文献   

6.
通过对盐城一深基坑支护设计对周边六层浅基础建筑的影响分析$结合现有相关的国家规范,从基坑周边土体和建筑物变形两个方面综合分析,阐述了深基坑设计过程中,如何对支护周边地表沉降进行计算控制,以保证周边建筑物的安全,同时取得最优经济效益。  相似文献   

7.
介绍了冰雪冻融作用下建筑地基沉降的研究现状,在考虑极端冰雪灾害条件下修正了已有的建筑物地基沉降公式,根据试验结果分析了冻融循环对地基沉降的影响程度,最后通过一个典型实例计算出在极端冰雪灾害影响下修正压缩模量后的地基沉降量。结果表明:当压缩模量发生明显变化时建筑地基受影响地层沉降量变化明显,整体沉降增加;当压缩模量受影响变化不大时,沉降量变化很小,可以不把极端冰雪灾害的影响作为主要因素考虑。  相似文献   

8.
高层建筑的基坑施工是高层建筑的基础,深基坑支护的施工是当前城市高层、超高层建筑突显的技术难题。结合工程实践,设计了施工方案,介绍了支护结构施工与土方开挖的方法,以对高层建筑提供有益的经验。  相似文献   

9.
高层建筑的基坑施工质量控制探讨   总被引:1,自引:0,他引:1  
秦俭 《科技信息》2010,(33):I0330-I0330,I0370
高层建筑的基坑施工是高层建筑的基础,深基坑支护的施工是当前城市高层、超高层建筑突显的技术难题。随着高层建筑的不断发展,深基坑施工已经成了建筑届关注的热点问题。笔者结合多年施工经验,根据多个工程的实际情况,总结分析了高层建筑深基坑支护施工过程的主要控制要点。  相似文献   

10.
孔劲  曹攀 《上海交通大学学报》2003,37(12):1847-1849
利用侧限压缩试验,研究了松散型砂在侧限应力状态下的力学行为,描述型砂压实状态的物理量,提出了型砂的瞬时压缩模量与压缩状态相关的假设.基于增量形式的广义虎克定律,推导了压实过程中与型砂的等效应变和初始状态量相关的瞬时压缩模量的数学表达式.构建了侧限压缩试验条件下幂函数形式的型砂本构关系,研究了型砂的重要状态量紧实率与所构建的型砂本构模型之间的关系,并用试验数据对理论推导的计算结果进行验证,结果吻合较好.  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.
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   

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.
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   

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.
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   

18.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

19.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号