共查询到20条相似文献，搜索用时 46 毫秒
1.
岩石和岩体是一种多晶复合介质,由于不同类型的岩石(火成岩、沉积岩、变质岩)成岩过程存在本质差异,以及经受历次地质构造运动和地质外营力作用,所以,概括在“岩石”(或岩体)这一术语下的介质的力学性态就显得非常复杂. 相似文献
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考虑体积变化影响的岩石应变软硬化损伤本构模型及参数确定方法 总被引：2，自引：0，他引：2
针对现有岩石损伤模型的局限性与不足,将应力作用下的岩石抽象为空隙、损伤与未损伤材料三部分,以空隙率反映岩石体积或空隙的变化,以损伤变量或损伤因子反映岩石力学性态的改变程度,通过对各部分材料的微观受力及其与宏观应力和应变的关系进行分析,建立了可反映岩石变形过程中体积或空隙变化特性的新型岩石损伤模型;从岩石微元强度合理度量方法研究入手,引进统计损伤理论,建立了可考虑损伤阀值影响的岩石统计损伤演化模型,进而建立了能模拟应变软硬化全过程的岩石统计损伤本构模型,并提出了参数确定方法。该模型不仅能反映岩石应变软硬化特性,而且能反映岩石变形的初期压密和后期扩容的特性。通过实例分析与讨论,表明模型合理与可行。 相似文献
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刚性试验机在岩石力学研究中的意义最近十多年来,岩石力学有了巨大的进展.当前,由于工程实践的需要,人们对有关岩石破坏的力学特性的研究内容,已不只是限于强度及破坏前的变形特性,而已把范围扩展到破坏后的阶段,即对应力应变一一的全过程的力学性态进行研究. 相似文献
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隧道衬砌冻胀压力问题研究 总被引：11，自引：1，他引：10
冻胀压力的量值和分布不仅取决于围岩的性态和气象条件,而且同衬砌结构的材料、刚度以及施工质量密切相关,从岩石和土层两种围岩中衬砌承受冻胀压力的机理出发,探讨其计算方法.通过计算分析,对寒冷地区隧道衬砌的设计和施工提出了若干建议. 相似文献
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本文指出了在微机上进行边坡稳定三维非线性有限元分析存在的困难，探讨了解决这些困难的方法，研制了一个能处理一般非线性问题，能模拟岩石性态、具有前后处理功能并便于在微机上运行的三维有限元分析程序，得到了一些有意义的结果。 相似文献
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成土母质之性质对於成土作用之影响,虽不若气候因子之大,但其对於风化作用之进行与夫土壤演变之过程实有不容忽视之力量,而尤以在岩石风化之初为甚,赣省侵蚀剧烈,沉积频繁,各类土壤或系岩石之新风化物,或与各期之沉积有关,故地质情形对於土壤之生成性态以及分布等关系异常密切,今请述之。 相似文献
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脆性作为岩石的重要的力学指标,对深部岩体性态评价以及灾害预防具有重要意义。岩石应力−应变曲线能够很好地表征岩石的脆性。考虑到现有基于应力−应变曲线的脆性指标大多都只对曲线的一部分进行分析,且少有指标能够准确地应用于岩石II类曲线中,对整体判断的缺乏可能会导致工程应用上适应性及可靠性不足的情况。针对现有脆性指标普遍存在的物理意义模糊、评估结果与岩石脆性的关系非连续等问题,综合考量岩石应力−应变曲线中峰前应力上升速率、峰后应力跌落速率以及峰值点应变值对岩石脆性的影响,提出了一种物理意义明确、计算结果与岩石脆性之间的关系是单调且连续的岩石脆性指数计算方法。选取国内外常用脆性指标对锦屏II级水电站大理岩和某铁路隧道花岗岩、变质砂岩以及片麻岩的单轴压缩试验数据进行脆性评价后进行比较,验证了指标的适用性。进一步将提出的指标应用于常规三轴试验条件下大理岩脆性分析,结果表明,该指标不仅能够量化和分类不同岩石的脆性特征,还能表征围压对岩石脆性的抑制作用。 相似文献
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脆性作为岩石的重要的力学指标,对深部岩体性态评价以及灾害预防具有重要意义。岩石应力-应变曲线能够很好地表征岩石的脆性。考虑到现有基于应力-应变曲线的脆性指标大多都只对曲线的一部分进行分析,且少有指标能够准确地应用于岩石Ⅱ类曲线中,对整体判断的缺乏可能会导致工程应用上适应性及可靠性不足的情况。针对现有脆性指标普遍存在的物理意义模糊、评估结果与岩石脆性的关系非连续等问题,综合考量岩石应力-应变曲线中峰前应力上升速率、峰后应力跌落速率以及峰值点应变值对岩石脆性的影响,提出了一种物理意义明确、计算结果与岩石脆性之间的关系是单调且连续的岩石脆性指数计算方法。选取国内外常用脆性指标对锦屏Ⅱ级水电站大理岩和某铁路隧道花岗岩、变质砂岩以及片麻岩的单轴压缩试验数据进行脆性评价后进行比较,验证了指标的适用性。进一步将提出的指标应用于常规三轴试验条件下大理岩脆性分析,结果表明,该指标不仅能够量化和分类不同岩石的脆性特征,还能表征围压对岩石脆性的抑制作用。 相似文献
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锚固技术是岩土工程中的一个主要支护手段之一,如何揭示锚索（杆）与岩石的复合作用机制锚固和失效形态,越来越成为关注的焦点。采用FLAC数值方法,对大试块横向含锚岩体的单轴压缩条件下力学性态进行了试验研究,结果表明：锚索（杆）与围岩的复合增强机制不仅与外载的大小有关,而且与锚固界面的力学性质有很大关系。随着锚固界面凝聚力的减小,锚固界面和锚索轴向的应力值都将减少,即锚索（杆）增强承载能力下降。当凝聚力减小到一定数值时,锚索（杆）将脱黏而产生滑动,导致锚固失效,因此,提高锚固界面的黏结力是保证锚固效果的关键之一。大试块锚固体的实验室岩石力学试验无论是试块加工还是试验过程,将十分困难和繁琐。采用数值模拟方法代替实验室试验,具有省时、经济、可视性强等优点,是今后研究锚固体力学性态的重要途径,具有推广应用价值。 相似文献
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Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
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Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
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The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
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Emmanuel Skourtsos Daniel Vachard Alexandra Zambetakis-Lekkas Rossana Martini Louisette Zaninetti 《Comptes Rendus Geoscience》2002,334(12):925-931
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931. 相似文献
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正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.) 相似文献
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正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.) 相似文献
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正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.) 相似文献
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正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus., 相似文献
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正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an 相似文献
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正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of 相似文献