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1.
以坝陵河悬索桥为例,鉴于锚碇式受到地形、地质条件的限制,在施工图设计阶段,进行坝陵河悬索桥西岸隧道式锚碇及其边坡的岩体工程地质力学研究.包括:锚碇围岩工程地质条件、锚碇围岩工程力学特性、锚碇围岩渗透及抗溶蚀特性等方面.  相似文献   

2.
广东虎门大桥东锚碇岩体稳定性分析   总被引:12,自引:0,他引:12  
阐述了锚碇区工程岩体的基本特征,并按国家岩体质量标准对工程岩体质量进行分,东锚碇体在虎门大桥主缆拉力作用下的稳定性分析分为物理模拟拔试验以及计算模型分析两部分,分析结果表明:在不考虑地地震力作用的情况下,锚碇岩体稳定系数大于2;随着地震加速度的增加,岩体稳定性急剧下降。  相似文献   

3.
运用岩体质量评价、现场模型试验、极限平衡法和FLAC3D数值仿真试验多种方法结合,对贵州坝陵河大桥西锚碇区围岩稳定性进行了研究.岩体质量评价表明,锚碇区岩体较破碎、质量差;现场模型试验发现,过大的位移将导致结构不能正常使用,锚体后锚面圆拱顶点、矩形底边中点及其6 m范围内的围岩变形较大.运用极限平衡法对边坡8种可能的破坏位置进行验算表明,边坡基本稳定,最危险滑动面发生在基坑上部的强风化、弱风化带岩体中.FLAC3D数值试验表明,围岩可能发生拉剪破坏,破损区集中在锚塞体后部右上角等5个部位,锚碇上部岩体水平位移大,位移等高线近半椭圆形扩散.设计和施工过程中,应对塑性区及显著变形区内的岩体重点加固.  相似文献   

4.
坝陵河大桥隧道锚围岩力学特性原位试验研究   总被引:4,自引:1,他引:3  
为全面认识坝陵河悬索桥西岸隧道锚的受力变形特性及安全稳定性,在分析研究锚碇区地层岩性特点基础上,利用相似性原理设计了与锚碇系统实际受力状态相适应的隧道锚原位模型试验系统,研究了原位试验加载及测试方法.试验成果表明,锚塞体混凝土和岩体在不同岩体条件下呈现出不同的变形特点:当岩体质量较好时,变形基本呈线性变化;当锚塞体周围岩体质量较差时,岩体的非线性变形特征明显.锚塞体与岩体之间的剪切残余变形表明锚塞体和岩体接触面在设计荷载作用下将产生较大的相对滑动.完整性较差岩体中的锚塞体变形远大于完整性较好情况下的锚塞体变形.  相似文献   

5.
为研究隧道锚的受力变形和锚碇承载特性等问题,在重庆几江长江大桥工程北岸现场开展1∶30缩尺模型试验。试验结果表明:从相似设计荷载240 kN 到1680 kN,双锚碇前锚面沿拉拔方向的最大位移平均值为0.020~0.808 mm,双锚碇前端上部地表岩体铅直方向的最大位移值为0.028~0.749 mm,双锚碇后端上部地表岩体铅直方向的最大位移值为0.014~0.645 mm;锚碇围岩破裂类型是拉剪复合型破坏;锚碇上方地表横桥方向参与抗拔作用的岩体范围约2~3 m,而沿锚碇轴向参与拉拔作用的岩体破坏区类似一个倒塞体形状;通过试验得到模型锚的可靠抗拉拔承载能力为1344 kN;模型锚在840 kN 下的流变趋于稳定,其长期安全系数为3.5。模型试验结果表明软岩地质条件下浅埋隧道锚具有较高的抗拉拔承载能力,证明此设计方案是可行的。  相似文献   

6.
为了解某大桥隧道锚碇及围岩体在张拉荷载下的变形状态及时效特性,采用三维显式有限差分软件FLAC3D对该大桥隧道锚碇系统进行三维粘弹塑性数值模拟.根据地质资料以及混凝土锚碇结构尺寸,建立隧道锚碇的三维计算模型,对岩体与锚碇之间的相互作用以及锚碇结构在长期荷载作用下的破坏模式进行研究,分析了由于施工开挖引起的锚碇和隧道围岩的位移及其应力变化.分析结果表明:当考虑岩体的流变力学特性后,在设计荷载作用下,锚碇和隧道围岩的变形均有所增加;与弹塑性计算结果比较,施加荷栽后经流变分析得到的隧道顶拱和底板的切向应力有所降低,拉应力的量值及拉应力区的范围减小,塑性区体积进一步扩大.  相似文献   

7.
李晓民 《甘肃科技》2009,25(10):100-102
悬索桥锚固系统在保证结构整体安全上具有重要控制作用。万州长江二桥的主桥锚碇,结合桥址地形,采用隧洞式锚碇结构。由于受三峡枢纽蓄水影响,锚碇处工程地质条件相对较差,为克服以上不利因素,在锚碇前端设置了预应力岩锚体系,主缆系统的锚固采用了先进的预应力锚固系统,在确保锚碇整体受力安全可靠的情况下,有效的控制了锚碇工程量,节省了工程投资。  相似文献   

8.
针对普立特大桥普立岸隧道式锚碇围岩系统的变形规律及破坏机制问题,采用有限差分法对其进行三维弹塑性模拟,分析了随着荷载的增加系统的塑性区、位移及应力的发展情况.数值结果表明:1设计缆力时,锚碇-围岩系统的位移均维持在mm级;继续加载,锚碇和周围岩体的位移形成的驼峰逐渐明显;至极限状态时,根据锚碇围岩的位移矢量图可勾勒出围岩的破坏范围,其中锚碇上、下部围岩的破坏范围分别为锚碇后锚面宽度的1.1倍和0.5倍;2系统在设计缆力下具有足够的安全稳定性,加载至8倍缆力时,锚碇的环向和径向的围岩塑性区均达到贯通,加载至极限状态时,锚碇周围岩体的塑性区分布形态呈倒塞体状;3根据监测点的位移变化、锚碇围岩塑性区分布及应力扩展情况得到,系统的破坏由锚碇带动周边部分岩体发生整体拉-剪破坏.  相似文献   

9.
通过对四川某公路边坡缓倾角层状岩体结构面的研究,认为结构面分布具有独特性,提出应按岩性及结构面性状进行分级的方案;同时分析研究了各类结构面的成因,认为Ⅰ级结构面是沉积作用形成的,Ⅱ级结构面是在Ⅲ级结构面基础上形成的,Ⅲ级结构面是构造作用形成的。  相似文献   

10.
抽水蓄能电站地下厂房轴线方向选择是前期勘察工作的重点.以芝瑞电站为工程背景,所研究的地下厂房围岩岩性为熔岩角砾岩,岩性较单一,结构面以Ⅳ级、Ⅴ级为主,岩体裂隙发育,完整性差,岩体结构以镶嵌~次块状结构为主.以块体理论为基础,运用Unwedge程序,充分分析不同结构面组合切割下的围岩稳定情况,以最小安全系数的最大值为取值原则,对复杂裂隙岩体环境下地下厂房轴线方向优化选择进行了系统研究.结果表明:研究区地下厂房轴线方向宜为NE50°.通过分析证明,块体理论在中低地应力区复杂裂隙岩体环境下地下厂房轴线方向优化选择中具有重要的现实意义.  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.
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   

14.
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   

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.
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   

18.
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   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

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