共查询到20条相似文献，搜索用时 63 毫秒
1.
依据渤海海冰物理和力学特征值和国内水池实验室能力,以1:10～1:30比尺要求,发展了DUT-1合成模型冰.文中简介该模型冰的理想参数、成分和制备过程.就其弯曲强度和弹性模量进行系统的实验分析.通过500多次弯曲实验,获得该模型冰在不同加载速度下的破坏方式,各向同性证据和弯曲强度为35～65kPa和弹性模量平均53MPa的结果.并且得到弯曲强度和弹性模量在实测湿密度范围内呈递增关系,浸水模型冰性能稳定时间超过4h,弹性模量与弯曲强度之比82%超过2000. 相似文献
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为精确模拟流动边界条件,克服边界形状复杂、长宽尺度相差悬殊及由于水位变化引起计算边界变化等困难,针对天然河道边界弯曲复杂等特点,应用水动力学和热力学等原理,建立了适体坐标下的二维河冰数值模型,模型主要包括流速场,水温沿河道变化,水内冰浓度分布,面冰输移,冰盖推进、稳定和消融,冰盖下冰的输移、堆积和冲蚀等,考虑了冰盖底部水中冰堆积和冰盖前沿形状对封冻过程的影响。采用MacCormack步进格式计算方法,并应用黄河河曲段实测资料对数值模拟结果进行了验证。验证结果表明,提出的数值模型能较好地体现河道的封冻过程。 相似文献
3.
细粒酒精模型冰单轴压缩强度特征试验研究 总被引：5，自引：0，他引：5
介绍细粒酒精模型冰的单轴压缩强度试验研究的方法和结果．试验采用两种试样,即长方形和哑铃形．对长方形试样发生不同破坏模式发生的条件,即试样尺寸、加载速度和压头与试样接触面摩擦等效应进行了详细讨论．描述了细粒酒精模型冰单轴压缩强度的基本特征,并比较了两种试样的试验结果． 相似文献
4.
半圆型结构冰压力的物理模拟试验研究 总被引：4，自引：0，他引：4
利用DUT-1非冻结合成模型冰开展1:25冰对半圆型构件的物理模拟试验研究. 首先用简单的斜面构件的物理模拟试验检验了整体试验装置和技术设备的可靠性, 然后以同样比尺进行2种冰厚在5个不同水位条件的系列试验, 获得了模型冰排在半圆型构件前的破碎堆积现象和作用于构件上的水平和垂直作用力过程.结合实测模型冰物理和力学指标, 通过优化组合, 拟合出半圆型防波堤冰荷载的试验公式. 这些公式包含了冰对半圆型结构的弯曲破坏作用力、挤压破坏作用力及爬坡和堆积作用力. 相似文献
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为研究冻土/岩内液相吸力和固相冰压在冻结过程中的作用机制,首先根据热力学基本原理,统一了不同边界条件下的理论冰压方程;然后,联立广义Clapeyron方程和Gibbs-Thomson方程,在阐释液相吸力和固相冰压物理意义基础上,给出了弯曲界面液相水的冻结温度方程;最后,将冻结温度方程引入冻结毛细管模型,将液相吸力方程代入达西定律,分别对固相冰压和液相吸力作用机制进行验证。研究表明：（1）平衡状态下的理论冰压仅与温度线性相关,与边界条件无关;（2）液相吸力来源于理论吸力与固相冰压抵消因子之差,为水分迁移统一驱动力,当固相冰压趋近于理论冰压时,液相吸力趋近于0;(3)固相冰压为绝对压力,可抵消液相吸力,而液相吸力为相对吸力,不可抵消固相冰压;（4）孔隙内的总压力仅为固相冰压,在毛细管冻结时,可达到平衡状态下的理论冰压,故遵循冰压法分凝冰形成机制。研究结果揭示了冻土/岩的液相吸力与固相冰压作用机制,对完善现有冻胀理论具有较高的理论价值和科学意义。 相似文献
6.
饱和颗粒正冻土-维刚性冰模型的数值模拟 总被引：1，自引：0，他引：1
基于刚性冰模型，应用有限差分法离散方程组，对于饱和颗粒土开放系统的冻结过程进行了一维数值模拟，给出了冻结缘内参数的分布．计算过程中修正了刚性冰模型中分凝冰产生条件，提出以冻结缘内冰压与载荷的关系作为分凝冰产生的判据，计算得到的冻胀量与实验室冻胀实验的测量数据较为吻合．将计算结果与现场实测资料进行了比较，温度场、含水量分布等结果在分布规律方面与现场实测资料相符． 相似文献
7.
基于渤海海冰的物理和力学特性、海冰物理模型试验的相似理论以及国际上已有模型冰的经验, 研制了一种用于模拟我国渤海海冰的非冻结可破碎功能材料, 被命名为DUT-1模型冰.该模型冰采用聚丙烯粉、塑料微珠、水泥等材料加入一定量的水由特制的搅拌机搅拌均匀倒入模具后成型制成.通过实验室常温波流水槽中进行的冰排对直桩、锥体及斜面墙结构作用的物模实验的现象观察、结果综合分析、相关理论及经验公式计算结果比较, 验证了DUT-1模型冰试验技术的可靠性.在此基础上, 进行了冰排对半圆型防波堤结构的作用、冰排与锥体结构动力相互作用的物理模型试验研究, 展现了DUT-1模型冰的应用前景. 相似文献
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通过区内505和530等主要矿脉石英红外吸收光谱、热爆裂及热发咣特征的系统研究，总结了该区无矿、贫矿及矿体石英脉评价的石英矿物学标志，表现为：①无矿石英起爆温度为210－330℃，热爆裂曲线无明显峰型；石英热发光总强度大于20000cps，峰值强度大于500cps;②贫金石英脉其石英红外吸收相对光密度DCO2／DH2O值大于1．1；起爆温度为210－280℃，石英热爆裂曲线为明显单峰形态，主爆峰对应温度值为420－440℃；石英热发光总强度介于10000－20000cps之间，峰值强度介于150－300cps之间；③矿体石英脉其石英红外吸收相对光密度DCO2／DH2O值小于1．0；起爆温度100－160℃，热爆曲线为单峰型，主爆峰对应温度为140－180℃；石英热发光总强度值小于10000cps，峰值强度小于150cps。根据本区含金矿脉矿化分带模式及石英红外吸收光谱、热及热发光参数系统变化规律，建立了该区石英脉型金矿床找矿评价的石英矿物学标志模型。 相似文献
11.
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
12.
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
13.
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
14.
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